feat(vanilla): add testing infrastructure and tests (NK-wjnczv)

1 files changed, 2372 insertions, 0 deletions

diff --git a/vanilla/node_modules/undici/lib/web/fetch/index.js b/vanilla/node_modules/undici/lib/web/fetch/index.js
new file mode 100644
index 0000000..f350035
--- /dev/null
+++ b/vanilla/node_modules/undici/lib/web/fetch/index.js
@@ -0,0 +1,2372 @@
+// https://github.com/Ethan-Arrowood/undici-fetch
+
+'use strict'
+
+const {
+  makeNetworkError,
+  makeAppropriateNetworkError,
+  filterResponse,
+  makeResponse,
+  fromInnerResponse,
+  getResponseState
+} = require('./response')
+const { HeadersList } = require('./headers')
+const { Request, cloneRequest, getRequestDispatcher, getRequestState } = require('./request')
+const zlib = require('node:zlib')
+const {
+  makePolicyContainer,
+  clonePolicyContainer,
+  requestBadPort,
+  TAOCheck,
+  appendRequestOriginHeader,
+  responseLocationURL,
+  requestCurrentURL,
+  setRequestReferrerPolicyOnRedirect,
+  tryUpgradeRequestToAPotentiallyTrustworthyURL,
+  createOpaqueTimingInfo,
+  appendFetchMetadata,
+  corsCheck,
+  crossOriginResourcePolicyCheck,
+  determineRequestsReferrer,
+  coarsenedSharedCurrentTime,
+  sameOrigin,
+  isCancelled,
+  isAborted,
+  isErrorLike,
+  fullyReadBody,
+  readableStreamClose,
+  urlIsLocal,
+  urlIsHttpHttpsScheme,
+  urlHasHttpsScheme,
+  clampAndCoarsenConnectionTimingInfo,
+  simpleRangeHeaderValue,
+  buildContentRange,
+  createInflate,
+  extractMimeType,
+  hasAuthenticationEntry,
+  includesCredentials,
+  isTraversableNavigable
+} = require('./util')
+const assert = require('node:assert')
+const { safelyExtractBody, extractBody } = require('./body')
+const {
+  redirectStatusSet,
+  nullBodyStatus,
+  safeMethodsSet,
+  requestBodyHeader,
+  subresourceSet
+} = require('./constants')
+const EE = require('node:events')
+const { Readable, pipeline, finished, isErrored, isReadable } = require('node:stream')
+const { addAbortListener, bufferToLowerCasedHeaderName } = require('../../core/util')
+const { dataURLProcessor, serializeAMimeType, minimizeSupportedMimeType } = require('./data-url')
+const { getGlobalDispatcher } = require('../../global')
+const { webidl } = require('../webidl')
+const { STATUS_CODES } = require('node:http')
+const { bytesMatch } = require('../subresource-integrity/subresource-integrity')
+const { createDeferredPromise } = require('../../util/promise')
+const { isomorphicEncode } = require('../infra')
+const { runtimeFeatures } = require('../../util/runtime-features')
+
+// Node.js v23.8.0+ and v22.15.0+ supports Zstandard
+const hasZstd = runtimeFeatures.has('zstd')
+
+const GET_OR_HEAD = ['GET', 'HEAD']
+
+const defaultUserAgent = typeof __UNDICI_IS_NODE__ !== 'undefined' || typeof esbuildDetection !== 'undefined'
+  ? 'node'
+  : 'undici'
+
+/** @type {import('buffer').resolveObjectURL} */
+let resolveObjectURL
+
+class Fetch extends EE {
+  constructor (dispatcher) {
+    super()
+
+    this.dispatcher = dispatcher
+    this.connection = null
+    this.dump = false
+    this.state = 'ongoing'
+  }
+
+  terminate (reason) {
+    if (this.state !== 'ongoing') {
+      return
+    }
+
+    this.state = 'terminated'
+    this.connection?.destroy(reason)
+    this.emit('terminated', reason)
+  }
+
+  // https://fetch.spec.whatwg.org/#fetch-controller-abort
+  abort (error) {
+    if (this.state !== 'ongoing') {
+      return
+    }
+
+    // 1. Set controller’s state to "aborted".
+    this.state = 'aborted'
+
+    // 2. Let fallbackError be an "AbortError" DOMException.
+    // 3. Set error to fallbackError if it is not given.
+    if (!error) {
+      error = new DOMException('The operation was aborted.', 'AbortError')
+    }
+
+    // 4. Let serializedError be StructuredSerialize(error).
+    //    If that threw an exception, catch it, and let
+    //    serializedError be StructuredSerialize(fallbackError).
+
+    // 5. Set controller’s serialized abort reason to serializedError.
+    this.serializedAbortReason = error
+
+    this.connection?.destroy(error)
+    this.emit('terminated', error)
+  }
+}
+
+function handleFetchDone (response) {
+  finalizeAndReportTiming(response, 'fetch')
+}
+
+// https://fetch.spec.whatwg.org/#fetch-method
+function fetch (input, init = undefined) {
+  webidl.argumentLengthCheck(arguments, 1, 'globalThis.fetch')
+
+  // 1. Let p be a new promise.
+  let p = createDeferredPromise()
+
+  // 2. Let requestObject be the result of invoking the initial value of
+  // Request as constructor with input and init as arguments. If this throws
+  // an exception, reject p with it and return p.
+  let requestObject
+
+  try {
+    requestObject = new Request(input, init)
+  } catch (e) {
+    p.reject(e)
+    return p.promise
+  }
+
+  // 3. Let request be requestObject’s request.
+  const request = getRequestState(requestObject)
+
+  // 4. If requestObject’s signal’s aborted flag is set, then:
+  if (requestObject.signal.aborted) {
+    // 1. Abort the fetch() call with p, request, null, and
+    //    requestObject’s signal’s abort reason.
+    abortFetch(p, request, null, requestObject.signal.reason, null)
+
+    // 2. Return p.
+    return p.promise
+  }
+
+  // 5. Let globalObject be request’s client’s global object.
+  const globalObject = request.client.globalObject
+
+  // 6. If globalObject is a ServiceWorkerGlobalScope object, then set
+  // request’s service-workers mode to "none".
+  if (globalObject?.constructor?.name === 'ServiceWorkerGlobalScope') {
+    request.serviceWorkers = 'none'
+  }
+
+  // 7. Let responseObject be null.
+  let responseObject = null
+
+  // 8. Let relevantRealm be this’s relevant Realm.
+
+  // 9. Let locallyAborted be false.
+  let locallyAborted = false
+
+  // 10. Let controller be null.
+  let controller = null
+
+  // 11. Add the following abort steps to requestObject’s signal:
+  addAbortListener(
+    requestObject.signal,
+    () => {
+      // 1. Set locallyAborted to true.
+      locallyAborted = true
+
+      // 2. Assert: controller is non-null.
+      assert(controller != null)
+
+      // 3. Abort controller with requestObject’s signal’s abort reason.
+      controller.abort(requestObject.signal.reason)
+
+      const realResponse = responseObject?.deref()
+
+      // 4. Abort the fetch() call with p, request, responseObject,
+      //    and requestObject’s signal’s abort reason.
+      abortFetch(p, request, realResponse, requestObject.signal.reason, controller.controller)
+    }
+  )
+
+  // 12. Let handleFetchDone given response response be to finalize and
+  // report timing with response, globalObject, and "fetch".
+  // see function handleFetchDone
+
+  // 13. Set controller to the result of calling fetch given request,
+  // with processResponseEndOfBody set to handleFetchDone, and processResponse
+  // given response being these substeps:
+
+  const processResponse = (response) => {
+    // 1. If locallyAborted is true, terminate these substeps.
+    if (locallyAborted) {
+      return
+    }
+
+    // 2. If response’s aborted flag is set, then:
+    if (response.aborted) {
+      // 1. Let deserializedError be the result of deserialize a serialized
+      //    abort reason given controller’s serialized abort reason and
+      //    relevantRealm.
+
+      // 2. Abort the fetch() call with p, request, responseObject, and
+      //    deserializedError.
+
+      abortFetch(p, request, responseObject, controller.serializedAbortReason, controller.controller)
+      return
+    }
+
+    // 3. If response is a network error, then reject p with a TypeError
+    // and terminate these substeps.
+    if (response.type === 'error') {
+      p.reject(new TypeError('fetch failed', { cause: response.error }))
+      return
+    }
+
+    // 4. Set responseObject to the result of creating a Response object,
+    // given response, "immutable", and relevantRealm.
+    responseObject = new WeakRef(fromInnerResponse(response, 'immutable'))
+
+    // 5. Resolve p with responseObject.
+    p.resolve(responseObject.deref())
+    p = null
+  }
+
+  controller = fetching({
+    request,
+    processResponseEndOfBody: handleFetchDone,
+    processResponse,
+    dispatcher: getRequestDispatcher(requestObject) // undici
+  })
+
+  // 14. Return p.
+  return p.promise
+}
+
+// https://fetch.spec.whatwg.org/#finalize-and-report-timing
+function finalizeAndReportTiming (response, initiatorType = 'other') {
+  // 1. If response is an aborted network error, then return.
+  if (response.type === 'error' && response.aborted) {
+    return
+  }
+
+  // 2. If response’s URL list is null or empty, then return.
+  if (!response.urlList?.length) {
+    return
+  }
+
+  // 3. Let originalURL be response’s URL list[0].
+  const originalURL = response.urlList[0]
+
+  // 4. Let timingInfo be response’s timing info.
+  let timingInfo = response.timingInfo
+
+  // 5. Let cacheState be response’s cache state.
+  let cacheState = response.cacheState
+
+  // 6. If originalURL’s scheme is not an HTTP(S) scheme, then return.
+  if (!urlIsHttpHttpsScheme(originalURL)) {
+    return
+  }
+
+  // 7. If timingInfo is null, then return.
+  if (timingInfo === null) {
+    return
+  }
+
+  // 8. If response’s timing allow passed flag is not set, then:
+  if (!response.timingAllowPassed) {
+    //  1. Set timingInfo to a the result of creating an opaque timing info for timingInfo.
+    timingInfo = createOpaqueTimingInfo({
+      startTime: timingInfo.startTime
+    })
+
+    //  2. Set cacheState to the empty string.
+    cacheState = ''
+  }
+
+  // 9. Set timingInfo’s end time to the coarsened shared current time
+  // given global’s relevant settings object’s cross-origin isolated
+  // capability.
+  // TODO: given global’s relevant settings object’s cross-origin isolated
+  // capability?
+  timingInfo.endTime = coarsenedSharedCurrentTime()
+
+  // 10. Set response’s timing info to timingInfo.
+  response.timingInfo = timingInfo
+
+  // 11. Mark resource timing for timingInfo, originalURL, initiatorType,
+  // global, and cacheState.
+  markResourceTiming(
+    timingInfo,
+    originalURL.href,
+    initiatorType,
+    globalThis,
+    cacheState,
+    '', // bodyType
+    response.status
+  )
+}
+
+// https://w3c.github.io/resource-timing/#dfn-mark-resource-timing
+const markResourceTiming = performance.markResourceTiming
+
+// https://fetch.spec.whatwg.org/#abort-fetch
+function abortFetch (p, request, responseObject, error, controller /* undici-specific */) {
+  // 1. Reject promise with error.
+  if (p) {
+    // We might have already resolved the promise at this stage
+    p.reject(error)
+  }
+
+  // 2. If request’s body is not null and is readable, then cancel request’s
+  // body with error.
+  if (request.body?.stream != null && isReadable(request.body.stream)) {
+    request.body.stream.cancel(error).catch((err) => {
+      if (err.code === 'ERR_INVALID_STATE') {
+        // Node bug?
+        return
+      }
+      throw err
+    })
+  }
+
+  // 3. If responseObject is null, then return.
+  if (responseObject == null) {
+    return
+  }
+
+  // 4. Let response be responseObject’s response.
+  const response = getResponseState(responseObject)
+
+  // 5. If response’s body is not null and is readable, then error response’s
+  // body with error.
+  if (response.body?.stream != null && isReadable(response.body.stream)) {
+    controller.error(error)
+  }
+}
+
+// https://fetch.spec.whatwg.org/#fetching
+function fetching ({
+  request,
+  processRequestBodyChunkLength,
+  processRequestEndOfBody,
+  processResponse,
+  processResponseEndOfBody,
+  processResponseConsumeBody,
+  useParallelQueue = false,
+  dispatcher = getGlobalDispatcher() // undici
+}) {
+  // Ensure that the dispatcher is set accordingly
+  assert(dispatcher)
+
+  // 1. Let taskDestination be null.
+  let taskDestination = null
+
+  // 2. Let crossOriginIsolatedCapability be false.
+  let crossOriginIsolatedCapability = false
+
+  // 3. If request’s client is non-null, then:
+  if (request.client != null) {
+    // 1. Set taskDestination to request’s client’s global object.
+    taskDestination = request.client.globalObject
+
+    // 2. Set crossOriginIsolatedCapability to request’s client’s cross-origin
+    // isolated capability.
+    crossOriginIsolatedCapability =
+      request.client.crossOriginIsolatedCapability
+  }
+
+  // 4. If useParallelQueue is true, then set taskDestination to the result of
+  // starting a new parallel queue.
+  // TODO
+
+  // 5. Let timingInfo be a new fetch timing info whose start time and
+  // post-redirect start time are the coarsened shared current time given
+  // crossOriginIsolatedCapability.
+  const currentTime = coarsenedSharedCurrentTime(crossOriginIsolatedCapability)
+  const timingInfo = createOpaqueTimingInfo({
+    startTime: currentTime
+  })
+
+  // 6. Let fetchParams be a new fetch params whose
+  // request is request,
+  // timing info is timingInfo,
+  // process request body chunk length is processRequestBodyChunkLength,
+  // process request end-of-body is processRequestEndOfBody,
+  // process response is processResponse,
+  // process response consume body is processResponseConsumeBody,
+  // process response end-of-body is processResponseEndOfBody,
+  // task destination is taskDestination,
+  // and cross-origin isolated capability is crossOriginIsolatedCapability.
+  const fetchParams = {
+    controller: new Fetch(dispatcher),
+    request,
+    timingInfo,
+    processRequestBodyChunkLength,
+    processRequestEndOfBody,
+    processResponse,
+    processResponseConsumeBody,
+    processResponseEndOfBody,
+    taskDestination,
+    crossOriginIsolatedCapability
+  }
+
+  // 7. If request’s body is a byte sequence, then set request’s body to
+  //    request’s body as a body.
+  // NOTE: Since fetching is only called from fetch, body should already be
+  // extracted.
+  assert(!request.body || request.body.stream)
+
+  // 8. If request’s window is "client", then set request’s window to request’s
+  // client, if request’s client’s global object is a Window object; otherwise
+  // "no-window".
+  if (request.window === 'client') {
+    // TODO: What if request.client is null?
+    request.window =
+      request.client?.globalObject?.constructor?.name === 'Window'
+        ? request.client
+        : 'no-window'
+  }
+
+  // 9. If request’s origin is "client", then set request’s origin to request’s
+  // client’s origin.
+  if (request.origin === 'client') {
+    request.origin = request.client.origin
+  }
+
+  // 10. If all of the following conditions are true:
+  // TODO
+
+  // 11. If request’s policy container is "client", then:
+  if (request.policyContainer === 'client') {
+    // 1. If request’s client is non-null, then set request’s policy
+    // container to a clone of request’s client’s policy container. [HTML]
+    if (request.client != null) {
+      request.policyContainer = clonePolicyContainer(
+        request.client.policyContainer
+      )
+    } else {
+      // 2. Otherwise, set request’s policy container to a new policy
+      // container.
+      request.policyContainer = makePolicyContainer()
+    }
+  }
+
+  // 12. If request’s header list does not contain `Accept`, then:
+  if (!request.headersList.contains('accept', true)) {
+    // 1. Let value be `*/*`.
+    const value = '*/*'
+
+    // 2. A user agent should set value to the first matching statement, if
+    // any, switching on request’s destination:
+    // "document"
+    // "frame"
+    // "iframe"
+    // `text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8`
+    // "image"
+    // `image/png,image/svg+xml,image/*;q=0.8,*/*;q=0.5`
+    // "style"
+    // `text/css,*/*;q=0.1`
+    // TODO
+
+    // 3. Append `Accept`/value to request’s header list.
+    request.headersList.append('accept', value, true)
+  }
+
+  // 13. If request’s header list does not contain `Accept-Language`, then
+  // user agents should append `Accept-Language`/an appropriate value to
+  // request’s header list.
+  if (!request.headersList.contains('accept-language', true)) {
+    request.headersList.append('accept-language', '*', true)
+  }
+
+  // 14. If request’s priority is null, then use request’s initiator and
+  // destination appropriately in setting request’s priority to a
+  // user-agent-defined object.
+  if (request.priority === null) {
+    // TODO
+  }
+
+  // 15. If request is a subresource request, then:
+  if (subresourceSet.has(request.destination)) {
+    // TODO
+  }
+
+  // 16. Run main fetch given fetchParams.
+  mainFetch(fetchParams, false)
+
+  // 17. Return fetchParam's controller
+  return fetchParams.controller
+}
+
+// https://fetch.spec.whatwg.org/#concept-main-fetch
+async function mainFetch (fetchParams, recursive) {
+  try {
+    // 1. Let request be fetchParams’s request.
+    const request = fetchParams.request
+
+    // 2. Let response be null.
+    let response = null
+
+    // 3. If request’s local-URLs-only flag is set and request’s current URL is
+    // not local, then set response to a network error.
+    if (request.localURLsOnly && !urlIsLocal(requestCurrentURL(request))) {
+      response = makeNetworkError('local URLs only')
+    }
+
+    // 4. Run report Content Security Policy violations for request.
+    // TODO
+
+    // 5. Upgrade request to a potentially trustworthy URL, if appropriate.
+    tryUpgradeRequestToAPotentiallyTrustworthyURL(request)
+
+    // 6. If should request be blocked due to a bad port, should fetching request
+    // be blocked as mixed content, or should request be blocked by Content
+    // Security Policy returns blocked, then set response to a network error.
+    if (requestBadPort(request) === 'blocked') {
+      response = makeNetworkError('bad port')
+    }
+    // TODO: should fetching request be blocked as mixed content?
+    // TODO: should request be blocked by Content Security Policy?
+
+    // 7. If request’s referrer policy is the empty string, then set request’s
+    // referrer policy to request’s policy container’s referrer policy.
+    if (request.referrerPolicy === '') {
+      request.referrerPolicy = request.policyContainer.referrerPolicy
+    }
+
+    // 8. If request’s referrer is not "no-referrer", then set request’s
+    // referrer to the result of invoking determine request’s referrer.
+    if (request.referrer !== 'no-referrer') {
+      request.referrer = determineRequestsReferrer(request)
+    }
+
+    // 9. Set request’s current URL’s scheme to "https" if all of the following
+    // conditions are true:
+    // - request’s current URL’s scheme is "http"
+    // - request’s current URL’s host is a domain
+    // - Matching request’s current URL’s host per Known HSTS Host Domain Name
+    //   Matching results in either a superdomain match with an asserted
+    //   includeSubDomains directive or a congruent match (with or without an
+    //   asserted includeSubDomains directive). [HSTS]
+    // TODO
+
+    // 10. If recursive is false, then run the remaining steps in parallel.
+    // TODO
+
+    // 11. If response is null, then set response to the result of running
+    // the steps corresponding to the first matching statement:
+    if (response === null) {
+      const currentURL = requestCurrentURL(request)
+      if (
+        // - request’s current URL’s origin is same origin with request’s origin,
+        //   and request’s response tainting is "basic"
+        (sameOrigin(currentURL, request.url) && request.responseTainting === 'basic') ||
+        // request’s current URL’s scheme is "data"
+        (currentURL.protocol === 'data:') ||
+        // - request’s mode is "navigate" or "websocket"
+        (request.mode === 'navigate' || request.mode === 'websocket')
+      ) {
+        // 1. Set request’s response tainting to "basic".
+        request.responseTainting = 'basic'
+
+        // 2. Return the result of running scheme fetch given fetchParams.
+        response = await schemeFetch(fetchParams)
+
+      // request’s mode is "same-origin"
+      } else if (request.mode === 'same-origin') {
+        // 1. Return a network error.
+        response = makeNetworkError('request mode cannot be "same-origin"')
+
+      // request’s mode is "no-cors"
+      } else if (request.mode === 'no-cors') {
+        // 1. If request’s redirect mode is not "follow", then return a network
+        // error.
+        if (request.redirect !== 'follow') {
+          response = makeNetworkError(
+            'redirect mode cannot be "follow" for "no-cors" request'
+          )
+        } else {
+          // 2. Set request’s response tainting to "opaque".
+          request.responseTainting = 'opaque'
+
+          // 3. Return the result of running scheme fetch given fetchParams.
+          response = await schemeFetch(fetchParams)
+        }
+      // request’s current URL’s scheme is not an HTTP(S) scheme
+      } else if (!urlIsHttpHttpsScheme(requestCurrentURL(request))) {
+        // Return a network error.
+        response = makeNetworkError('URL scheme must be a HTTP(S) scheme')
+
+        // - request’s use-CORS-preflight flag is set
+        // - request’s unsafe-request flag is set and either request’s method is
+        //   not a CORS-safelisted method or CORS-unsafe request-header names with
+        //   request’s header list is not empty
+        //    1. Set request’s response tainting to "cors".
+        //    2. Let corsWithPreflightResponse be the result of running HTTP fetch
+        //    given fetchParams and true.
+        //    3. If corsWithPreflightResponse is a network error, then clear cache
+        //    entries using request.
+        //    4. Return corsWithPreflightResponse.
+        // TODO
+
+      // Otherwise
+      } else {
+        //    1. Set request’s response tainting to "cors".
+        request.responseTainting = 'cors'
+
+        //    2. Return the result of running HTTP fetch given fetchParams.
+        response = await httpFetch(fetchParams)
+      }
+    }
+
+    // 12. If recursive is true, then return response.
+    if (recursive) {
+      return response
+    }
+
+    // 13. If response is not a network error and response is not a filtered
+    // response, then:
+    if (response.status !== 0 && !response.internalResponse) {
+      // If request’s response tainting is "cors", then:
+      if (request.responseTainting === 'cors') {
+        // 1. Let headerNames be the result of extracting header list values
+        // given `Access-Control-Expose-Headers` and response’s header list.
+        // TODO
+        // 2. If request’s credentials mode is not "include" and headerNames
+        // contains `*`, then set response’s CORS-exposed header-name list to
+        // all unique header names in response’s header list.
+        // TODO
+        // 3. Otherwise, if headerNames is not null or failure, then set
+        // response’s CORS-exposed header-name list to headerNames.
+        // TODO
+      }
+
+      // Set response to the following filtered response with response as its
+      // internal response, depending on request’s response tainting:
+      if (request.responseTainting === 'basic') {
+        response = filterResponse(response, 'basic')
+      } else if (request.responseTainting === 'cors') {
+        response = filterResponse(response, 'cors')
+      } else if (request.responseTainting === 'opaque') {
+        response = filterResponse(response, 'opaque')
+      } else {
+        assert(false)
+      }
+    }
+
+    // 14. Let internalResponse be response, if response is a network error,
+    // and response’s internal response otherwise.
+    let internalResponse =
+      response.status === 0 ? response : response.internalResponse
+
+    // 15. If internalResponse’s URL list is empty, then set it to a clone of
+    // request’s URL list.
+    if (internalResponse.urlList.length === 0) {
+      internalResponse.urlList.push(...request.urlList)
+    }
+
+    // 16. If request’s timing allow failed flag is unset, then set
+    // internalResponse’s timing allow passed flag.
+    if (!request.timingAllowFailed) {
+      response.timingAllowPassed = true
+    }
+
+    // 17. If response is not a network error and any of the following returns
+    // blocked
+    // - should internalResponse to request be blocked as mixed content
+    // - should internalResponse to request be blocked by Content Security Policy
+    // - should internalResponse to request be blocked due to its MIME type
+    // - should internalResponse to request be blocked due to nosniff
+    // TODO
+
+    // 18. If response’s type is "opaque", internalResponse’s status is 206,
+    // internalResponse’s range-requested flag is set, and request’s header
+    // list does not contain `Range`, then set response and internalResponse
+    // to a network error.
+    if (
+      response.type === 'opaque' &&
+      internalResponse.status === 206 &&
+      internalResponse.rangeRequested &&
+      !request.headers.contains('range', true)
+    ) {
+      response = internalResponse = makeNetworkError()
+    }
+
+    // 19. If response is not a network error and either request’s method is
+    // `HEAD` or `CONNECT`, or internalResponse’s status is a null body status,
+    // set internalResponse’s body to null and disregard any enqueuing toward
+    // it (if any).
+    if (
+      response.status !== 0 &&
+      (request.method === 'HEAD' ||
+        request.method === 'CONNECT' ||
+        nullBodyStatus.includes(internalResponse.status))
+    ) {
+      internalResponse.body = null
+      fetchParams.controller.dump = true
+    }
+
+    // 20. If request’s integrity metadata is not the empty string, then:
+    if (request.integrity) {
+      // 1. Let processBodyError be this step: run fetch finale given fetchParams
+      // and a network error.
+      const processBodyError = (reason) =>
+        fetchFinale(fetchParams, makeNetworkError(reason))
+
+      // 2. If request’s response tainting is "opaque", or response’s body is null,
+      // then run processBodyError and abort these steps.
+      if (request.responseTainting === 'opaque' || response.body == null) {
+        processBodyError(response.error)
+        return
+      }
+
+      // 3. Let processBody given bytes be these steps:
+      const processBody = (bytes) => {
+        // 1. If bytes do not match request’s integrity metadata,
+        // then run processBodyError and abort these steps. [SRI]
+        if (!bytesMatch(bytes, request.integrity)) {
+          processBodyError('integrity mismatch')
+          return
+        }
+
+        // 2. Set response’s body to bytes as a body.
+        response.body = safelyExtractBody(bytes)[0]
+
+        // 3. Run fetch finale given fetchParams and response.
+        fetchFinale(fetchParams, response)
+      }
+
+      // 4. Fully read response’s body given processBody and processBodyError.
+      fullyReadBody(response.body, processBody, processBodyError)
+    } else {
+      // 21. Otherwise, run fetch finale given fetchParams and response.
+      fetchFinale(fetchParams, response)
+    }
+  } catch (err) {
+    fetchParams.controller.terminate(err)
+  }
+}
+
+// https://fetch.spec.whatwg.org/#concept-scheme-fetch
+// given a fetch params fetchParams
+function schemeFetch (fetchParams) {
+  // Note: since the connection is destroyed on redirect, which sets fetchParams to a
+  // cancelled state, we do not want this condition to trigger *unless* there have been
+  // no redirects. See https://github.com/nodejs/undici/issues/1776
+  // 1. If fetchParams is canceled, then return the appropriate network error for fetchParams.
+  if (isCancelled(fetchParams) && fetchParams.request.redirectCount === 0) {
+    return Promise.resolve(makeAppropriateNetworkError(fetchParams))
+  }
+
+  // 2. Let request be fetchParams’s request.
+  const { request } = fetchParams
+
+  const { protocol: scheme } = requestCurrentURL(request)
+
+  // 3. Switch on request’s current URL’s scheme and run the associated steps:
+  switch (scheme) {
+    case 'about:': {
+      // If request’s current URL’s path is the string "blank", then return a new response
+      // whose status message is `OK`, header list is « (`Content-Type`, `text/html;charset=utf-8`) »,
+      // and body is the empty byte sequence as a body.
+
+      // Otherwise, return a network error.
+      return Promise.resolve(makeNetworkError('about scheme is not supported'))
+    }
+    case 'blob:': {
+      if (!resolveObjectURL) {
+        resolveObjectURL = require('node:buffer').resolveObjectURL
+      }
+
+      // 1. Let blobURLEntry be request’s current URL’s blob URL entry.
+      const blobURLEntry = requestCurrentURL(request)
+
+      // https://github.com/web-platform-tests/wpt/blob/7b0ebaccc62b566a1965396e5be7bb2bc06f841f/FileAPI/url/resources/fetch-tests.js#L52-L56
+      // Buffer.resolveObjectURL does not ignore URL queries.
+      if (blobURLEntry.search.length !== 0) {
+        return Promise.resolve(makeNetworkError('NetworkError when attempting to fetch resource.'))
+      }
+
+      const blob = resolveObjectURL(blobURLEntry.toString())
+
+      // 2. If request’s method is not `GET`, blobURLEntry is null, or blobURLEntry’s
+      //    object is not a Blob object, then return a network error.
+      if (request.method !== 'GET' || !webidl.is.Blob(blob)) {
+        return Promise.resolve(makeNetworkError('invalid method'))
+      }
+
+      // 3. Let blob be blobURLEntry’s object.
+      // Note: done above
+
+      // 4. Let response be a new response.
+      const response = makeResponse()
+
+      // 5. Let fullLength be blob’s size.
+      const fullLength = blob.size
+
+      // 6. Let serializedFullLength be fullLength, serialized and isomorphic encoded.
+      const serializedFullLength = isomorphicEncode(`${fullLength}`)
+
+      // 7. Let type be blob’s type.
+      const type = blob.type
+
+      // 8. If request’s header list does not contain `Range`:
+      // 9. Otherwise:
+      if (!request.headersList.contains('range', true)) {
+        // 1. Let bodyWithType be the result of safely extracting blob.
+        // Note: in the FileAPI a blob "object" is a Blob *or* a MediaSource.
+        // In node, this can only ever be a Blob. Therefore we can safely
+        // use extractBody directly.
+        const bodyWithType = extractBody(blob)
+
+        // 2. Set response’s status message to `OK`.
+        response.statusText = 'OK'
+
+        // 3. Set response’s body to bodyWithType’s body.
+        response.body = bodyWithType[0]
+
+        // 4. Set response’s header list to « (`Content-Length`, serializedFullLength), (`Content-Type`, type) ».
+        response.headersList.set('content-length', serializedFullLength, true)
+        response.headersList.set('content-type', type, true)
+      } else {
+        // 1. Set response’s range-requested flag.
+        response.rangeRequested = true
+
+        // 2. Let rangeHeader be the result of getting `Range` from request’s header list.
+        const rangeHeader = request.headersList.get('range', true)
+
+        // 3. Let rangeValue be the result of parsing a single range header value given rangeHeader and true.
+        const rangeValue = simpleRangeHeaderValue(rangeHeader, true)
+
+        // 4. If rangeValue is failure, then return a network error.
+        if (rangeValue === 'failure') {
+          return Promise.resolve(makeNetworkError('failed to fetch the data URL'))
+        }
+
+        // 5. Let (rangeStart, rangeEnd) be rangeValue.
+        let { rangeStartValue: rangeStart, rangeEndValue: rangeEnd } = rangeValue
+
+        // 6. If rangeStart is null:
+        // 7. Otherwise:
+        if (rangeStart === null) {
+          // 1. Set rangeStart to fullLength − rangeEnd.
+          rangeStart = fullLength - rangeEnd
+
+          // 2. Set rangeEnd to rangeStart + rangeEnd − 1.
+          rangeEnd = rangeStart + rangeEnd - 1
+        } else {
+          // 1. If rangeStart is greater than or equal to fullLength, then return a network error.
+          if (rangeStart >= fullLength) {
+            return Promise.resolve(makeNetworkError('Range start is greater than the blob\'s size.'))
+          }
+
+          // 2. If rangeEnd is null or rangeEnd is greater than or equal to fullLength, then set
+          //    rangeEnd to fullLength − 1.
+          if (rangeEnd === null || rangeEnd >= fullLength) {
+            rangeEnd = fullLength - 1
+          }
+        }
+
+        // 8. Let slicedBlob be the result of invoking slice blob given blob, rangeStart,
+        //    rangeEnd + 1, and type.
+        const slicedBlob = blob.slice(rangeStart, rangeEnd + 1, type)
+
+        // 9. Let slicedBodyWithType be the result of safely extracting slicedBlob.
+        // Note: same reason as mentioned above as to why we use extractBody
+        const slicedBodyWithType = extractBody(slicedBlob)
+
+        // 10. Set response’s body to slicedBodyWithType’s body.
+        response.body = slicedBodyWithType[0]
+
+        // 11. Let serializedSlicedLength be slicedBlob’s size, serialized and isomorphic encoded.
+        const serializedSlicedLength = isomorphicEncode(`${slicedBlob.size}`)
+
+        // 12. Let contentRange be the result of invoking build a content range given rangeStart,
+        //     rangeEnd, and fullLength.
+        const contentRange = buildContentRange(rangeStart, rangeEnd, fullLength)
+
+        // 13. Set response’s status to 206.
+        response.status = 206
+
+        // 14. Set response’s status message to `Partial Content`.
+        response.statusText = 'Partial Content'
+
+        // 15. Set response’s header list to « (`Content-Length`, serializedSlicedLength),
+        //     (`Content-Type`, type), (`Content-Range`, contentRange) ».
+        response.headersList.set('content-length', serializedSlicedLength, true)
+        response.headersList.set('content-type', type, true)
+        response.headersList.set('content-range', contentRange, true)
+      }
+
+      // 10. Return response.
+      return Promise.resolve(response)
+    }
+    case 'data:': {
+      // 1. Let dataURLStruct be the result of running the
+      //    data: URL processor on request’s current URL.
+      const currentURL = requestCurrentURL(request)
+      const dataURLStruct = dataURLProcessor(currentURL)
+
+      // 2. If dataURLStruct is failure, then return a
+      //    network error.
+      if (dataURLStruct === 'failure') {
+        return Promise.resolve(makeNetworkError('failed to fetch the data URL'))
+      }
+
+      // 3. Let mimeType be dataURLStruct’s MIME type, serialized.
+      const mimeType = serializeAMimeType(dataURLStruct.mimeType)
+
+      // 4. Return a response whose status message is `OK`,
+      //    header list is « (`Content-Type`, mimeType) »,
+      //    and body is dataURLStruct’s body as a body.
+      return Promise.resolve(makeResponse({
+        statusText: 'OK',
+        headersList: [
+          ['content-type', { name: 'Content-Type', value: mimeType }]
+        ],
+        body: safelyExtractBody(dataURLStruct.body)[0]
+      }))
+    }
+    case 'file:': {
+      // For now, unfortunate as it is, file URLs are left as an exercise for the reader.
+      // When in doubt, return a network error.
+      return Promise.resolve(makeNetworkError('not implemented... yet...'))
+    }
+    case 'http:':
+    case 'https:': {
+      // Return the result of running HTTP fetch given fetchParams.
+
+      return httpFetch(fetchParams)
+        .catch((err) => makeNetworkError(err))
+    }
+    default: {
+      return Promise.resolve(makeNetworkError('unknown scheme'))
+    }
+  }
+}
+
+// https://fetch.spec.whatwg.org/#finalize-response
+function finalizeResponse (fetchParams, response) {
+  // 1. Set fetchParams’s request’s done flag.
+  fetchParams.request.done = true
+
+  // 2, If fetchParams’s process response done is not null, then queue a fetch
+  // task to run fetchParams’s process response done given response, with
+  // fetchParams’s task destination.
+  if (fetchParams.processResponseDone != null) {
+    queueMicrotask(() => fetchParams.processResponseDone(response))
+  }
+}
+
+// https://fetch.spec.whatwg.org/#fetch-finale
+function fetchFinale (fetchParams, response) {
+  // 1. Let timingInfo be fetchParams’s timing info.
+  let timingInfo = fetchParams.timingInfo
+
+  // 2. If response is not a network error and fetchParams’s request’s client is a secure context,
+  //    then set timingInfo’s server-timing headers to the result of getting, decoding, and splitting
+  //    `Server-Timing` from response’s internal response’s header list.
+  // TODO
+
+  // 3. Let processResponseEndOfBody be the following steps:
+  const processResponseEndOfBody = () => {
+    // 1. Let unsafeEndTime be the unsafe shared current time.
+    const unsafeEndTime = Date.now() // ?
+
+    // 2. If fetchParams’s request’s destination is "document", then set fetchParams’s controller’s
+    //    full timing info to fetchParams’s timing info.
+    if (fetchParams.request.destination === 'document') {
+      fetchParams.controller.fullTimingInfo = timingInfo
+    }
+
+    // 3. Set fetchParams’s controller’s report timing steps to the following steps given a global object global:
+    fetchParams.controller.reportTimingSteps = () => {
+      // 1. If fetchParams’s request’s URL’s scheme is not an HTTP(S) scheme, then return.
+      if (!urlIsHttpHttpsScheme(fetchParams.request.url)) {
+        return
+      }
+
+      // 2. Set timingInfo’s end time to the relative high resolution time given unsafeEndTime and global.
+      timingInfo.endTime = unsafeEndTime
+
+      // 3. Let cacheState be response’s cache state.
+      let cacheState = response.cacheState
+
+      // 4. Let bodyInfo be response’s body info.
+      const bodyInfo = response.bodyInfo
+
+      // 5. If response’s timing allow passed flag is not set, then set timingInfo to the result of creating an
+      //    opaque timing info for timingInfo and set cacheState to the empty string.
+      if (!response.timingAllowPassed) {
+        timingInfo = createOpaqueTimingInfo(timingInfo)
+
+        cacheState = ''
+      }
+
+      // 6. Let responseStatus be 0.
+      let responseStatus = 0
+
+      // 7. If fetchParams’s request’s mode is not "navigate" or response’s has-cross-origin-redirects is false:
+      if (fetchParams.request.mode !== 'navigator' || !response.hasCrossOriginRedirects) {
+        // 1. Set responseStatus to response’s status.
+        responseStatus = response.status
+
+        // 2. Let mimeType be the result of extracting a MIME type from response’s header list.
+        const mimeType = extractMimeType(response.headersList)
+
+        // 3. If mimeType is not failure, then set bodyInfo’s content type to the result of minimizing a supported MIME type given mimeType.
+        if (mimeType !== 'failure') {
+          bodyInfo.contentType = minimizeSupportedMimeType(mimeType)
+        }
+      }
+
+      // 8. If fetchParams’s request’s initiator type is non-null, then mark resource timing given timingInfo,
+      //    fetchParams’s request’s URL, fetchParams’s request’s initiator type, global, cacheState, bodyInfo,
+      //    and responseStatus.
+      if (fetchParams.request.initiatorType != null) {
+        markResourceTiming(timingInfo, fetchParams.request.url.href, fetchParams.request.initiatorType, globalThis, cacheState, bodyInfo, responseStatus)
+      }
+    }
+
+    // 4. Let processResponseEndOfBodyTask be the following steps:
+    const processResponseEndOfBodyTask = () => {
+      // 1. Set fetchParams’s request’s done flag.
+      fetchParams.request.done = true
+
+      // 2. If fetchParams’s process response end-of-body is non-null, then run fetchParams’s process
+      //    response end-of-body given response.
+      if (fetchParams.processResponseEndOfBody != null) {
+        queueMicrotask(() => fetchParams.processResponseEndOfBody(response))
+      }
+
+      // 3. If fetchParams’s request’s initiator type is non-null and fetchParams’s request’s client’s
+      //    global object is fetchParams’s task destination, then run fetchParams’s controller’s report
+      //    timing steps given fetchParams’s request’s client’s global object.
+      if (fetchParams.request.initiatorType != null) {
+        fetchParams.controller.reportTimingSteps()
+      }
+    }
+
+    // 5. Queue a fetch task to run processResponseEndOfBodyTask with fetchParams’s task destination
+    queueMicrotask(() => processResponseEndOfBodyTask())
+  }
+
+  // 4. If fetchParams’s process response is non-null, then queue a fetch task to run fetchParams’s
+  //    process response given response, with fetchParams’s task destination.
+  if (fetchParams.processResponse != null) {
+    queueMicrotask(() => {
+      fetchParams.processResponse(response)
+      fetchParams.processResponse = null
+    })
+  }
+
+  // 5. Let internalResponse be response, if response is a network error; otherwise response’s internal response.
+  const internalResponse = response.type === 'error' ? response : (response.internalResponse ?? response)
+
+  // 6. If internalResponse’s body is null, then run processResponseEndOfBody.
+  // 7. Otherwise:
+  if (internalResponse.body == null) {
+    processResponseEndOfBody()
+  } else {
+    // mcollina: all the following steps of the specs are skipped.
+    // The internal transform stream is not needed.
+    // See https://github.com/nodejs/undici/pull/3093#issuecomment-2050198541
+
+    // 1. Let transformStream be a new TransformStream.
+    // 2. Let identityTransformAlgorithm be an algorithm which, given chunk, enqueues chunk in transformStream.
+    // 3. Set up transformStream with transformAlgorithm set to identityTransformAlgorithm and flushAlgorithm
+    //    set to processResponseEndOfBody.
+    // 4. Set internalResponse’s body’s stream to the result of internalResponse’s body’s stream piped through transformStream.
+
+    finished(internalResponse.body.stream, () => {
+      processResponseEndOfBody()
+    })
+  }
+}
+
+// https://fetch.spec.whatwg.org/#http-fetch
+async function httpFetch (fetchParams) {
+  // 1. Let request be fetchParams’s request.
+  const request = fetchParams.request
+
+  // 2. Let response be null.
+  let response = null
+
+  // 3. Let actualResponse be null.
+  let actualResponse = null
+
+  // 4. Let timingInfo be fetchParams’s timing info.
+  const timingInfo = fetchParams.timingInfo
+
+  // 5. If request’s service-workers mode is "all", then:
+  if (request.serviceWorkers === 'all') {
+    // TODO
+  }
+
+  // 6. If response is null, then:
+  if (response === null) {
+    // 1. If makeCORSPreflight is true and one of these conditions is true:
+    // TODO
+
+    // 2. If request’s redirect mode is "follow", then set request’s
+    // service-workers mode to "none".
+    if (request.redirect === 'follow') {
+      request.serviceWorkers = 'none'
+    }
+
+    // 3. Set response and actualResponse to the result of running
+    // HTTP-network-or-cache fetch given fetchParams.
+    actualResponse = response = await httpNetworkOrCacheFetch(fetchParams)
+
+    // 4. If request’s response tainting is "cors" and a CORS check
+    // for request and response returns failure, then return a network error.
+    if (
+      request.responseTainting === 'cors' &&
+      corsCheck(request, response) === 'failure'
+    ) {
+      return makeNetworkError('cors failure')
+    }
+
+    // 5. If the TAO check for request and response returns failure, then set
+    // request’s timing allow failed flag.
+    if (TAOCheck(request, response) === 'failure') {
+      request.timingAllowFailed = true
+    }
+  }
+
+  // 7. If either request’s response tainting or response’s type
+  // is "opaque", and the cross-origin resource policy check with
+  // request’s origin, request’s client, request’s destination,
+  // and actualResponse returns blocked, then return a network error.
+  if (
+    (request.responseTainting === 'opaque' || response.type === 'opaque') &&
+    crossOriginResourcePolicyCheck(
+      request.origin,
+      request.client,
+      request.destination,
+      actualResponse
+    ) === 'blocked'
+  ) {
+    return makeNetworkError('blocked')
+  }
+
+  // 8. If actualResponse’s status is a redirect status, then:
+  if (redirectStatusSet.has(actualResponse.status)) {
+    // 1. If actualResponse’s status is not 303, request’s body is not null,
+    // and the connection uses HTTP/2, then user agents may, and are even
+    // encouraged to, transmit an RST_STREAM frame.
+    // See, https://github.com/whatwg/fetch/issues/1288
+    if (request.redirect !== 'manual') {
+      fetchParams.controller.connection.destroy(undefined, false)
+    }
+
+    // 2. Switch on request’s redirect mode:
+    if (request.redirect === 'error') {
+      // Set response to a network error.
+      response = makeNetworkError('unexpected redirect')
+    } else if (request.redirect === 'manual') {
+      // Set response to an opaque-redirect filtered response whose internal
+      // response is actualResponse.
+      // NOTE(spec): On the web this would return an `opaqueredirect` response,
+      // but that doesn't make sense server side.
+      // See https://github.com/nodejs/undici/issues/1193.
+      response = actualResponse
+    } else if (request.redirect === 'follow') {
+      // Set response to the result of running HTTP-redirect fetch given
+      // fetchParams and response.
+      response = await httpRedirectFetch(fetchParams, response)
+    } else {
+      assert(false)
+    }
+  }
+
+  // 9. Set response’s timing info to timingInfo.
+  response.timingInfo = timingInfo
+
+  // 10. Return response.
+  return response
+}
+
+// https://fetch.spec.whatwg.org/#http-redirect-fetch
+function httpRedirectFetch (fetchParams, response) {
+  // 1. Let request be fetchParams’s request.
+  const request = fetchParams.request
+
+  // 2. Let actualResponse be response, if response is not a filtered response,
+  // and response’s internal response otherwise.
+  const actualResponse = response.internalResponse
+    ? response.internalResponse
+    : response
+
+  // 3. Let locationURL be actualResponse’s location URL given request’s current
+  // URL’s fragment.
+  let locationURL
+
+  try {
+    locationURL = responseLocationURL(
+      actualResponse,
+      requestCurrentURL(request).hash
+    )
+
+    // 4. If locationURL is null, then return response.
+    if (locationURL == null) {
+      return response
+    }
+  } catch (err) {
+    // 5. If locationURL is failure, then return a network error.
+    return Promise.resolve(makeNetworkError(err))
+  }
+
+  // 6. If locationURL’s scheme is not an HTTP(S) scheme, then return a network
+  // error.
+  if (!urlIsHttpHttpsScheme(locationURL)) {
+    return Promise.resolve(makeNetworkError('URL scheme must be a HTTP(S) scheme'))
+  }
+
+  // 7. If request’s redirect count is 20, then return a network error.
+  if (request.redirectCount === 20) {
+    return Promise.resolve(makeNetworkError('redirect count exceeded'))
+  }
+
+  // 8. Increase request’s redirect count by 1.
+  request.redirectCount += 1
+
+  // 9. If request’s mode is "cors", locationURL includes credentials, and
+  // request’s origin is not same origin with locationURL’s origin, then return
+  //  a network error.
+  if (
+    request.mode === 'cors' &&
+    (locationURL.username || locationURL.password) &&
+    !sameOrigin(request, locationURL)
+  ) {
+    return Promise.resolve(makeNetworkError('cross origin not allowed for request mode "cors"'))
+  }
+
+  // 10. If request’s response tainting is "cors" and locationURL includes
+  // credentials, then return a network error.
+  if (
+    request.responseTainting === 'cors' &&
+    (locationURL.username || locationURL.password)
+  ) {
+    return Promise.resolve(makeNetworkError(
+      'URL cannot contain credentials for request mode "cors"'
+    ))
+  }
+
+  // 11. If actualResponse’s status is not 303, request’s body is non-null,
+  // and request’s body’s source is null, then return a network error.
+  if (
+    actualResponse.status !== 303 &&
+    request.body != null &&
+    request.body.source == null
+  ) {
+    return Promise.resolve(makeNetworkError())
+  }
+
+  // 12. If one of the following is true
+  // - actualResponse’s status is 301 or 302 and request’s method is `POST`
+  // - actualResponse’s status is 303 and request’s method is not `GET` or `HEAD`
+  if (
+    ([301, 302].includes(actualResponse.status) && request.method === 'POST') ||
+    (actualResponse.status === 303 &&
+      !GET_OR_HEAD.includes(request.method))
+  ) {
+    // then:
+    // 1. Set request’s method to `GET` and request’s body to null.
+    request.method = 'GET'
+    request.body = null
+
+    // 2. For each headerName of request-body-header name, delete headerName from
+    // request’s header list.
+    for (const headerName of requestBodyHeader) {
+      request.headersList.delete(headerName)
+    }
+  }
+
+  // 13. If request’s current URL’s origin is not same origin with locationURL’s
+  //     origin, then for each headerName of CORS non-wildcard request-header name,
+  //     delete headerName from request’s header list.
+  if (!sameOrigin(requestCurrentURL(request), locationURL)) {
+    // https://fetch.spec.whatwg.org/#cors-non-wildcard-request-header-name
+    request.headersList.delete('authorization', true)
+
+    // https://fetch.spec.whatwg.org/#authentication-entries
+    request.headersList.delete('proxy-authorization', true)
+
+    // "Cookie" and "Host" are forbidden request-headers, which undici doesn't implement.
+    request.headersList.delete('cookie', true)
+    request.headersList.delete('host', true)
+  }
+
+  // 14. If request's body is non-null, then set request's body to the first return
+  // value of safely extracting request's body's source.
+  if (request.body != null) {
+    assert(request.body.source != null)
+    request.body = safelyExtractBody(request.body.source)[0]
+  }
+
+  // 15. Let timingInfo be fetchParams’s timing info.
+  const timingInfo = fetchParams.timingInfo
+
+  // 16. Set timingInfo’s redirect end time and post-redirect start time to the
+  // coarsened shared current time given fetchParams’s cross-origin isolated
+  // capability.
+  timingInfo.redirectEndTime = timingInfo.postRedirectStartTime =
+    coarsenedSharedCurrentTime(fetchParams.crossOriginIsolatedCapability)
+
+  // 17. If timingInfo’s redirect start time is 0, then set timingInfo’s
+  //  redirect start time to timingInfo’s start time.
+  if (timingInfo.redirectStartTime === 0) {
+    timingInfo.redirectStartTime = timingInfo.startTime
+  }
+
+  // 18. Append locationURL to request’s URL list.
+  request.urlList.push(locationURL)
+
+  // 19. Invoke set request’s referrer policy on redirect on request and
+  // actualResponse.
+  setRequestReferrerPolicyOnRedirect(request, actualResponse)
+
+  // 20. Return the result of running main fetch given fetchParams and true.
+  return mainFetch(fetchParams, true)
+}
+
+// https://fetch.spec.whatwg.org/#http-network-or-cache-fetch
+async function httpNetworkOrCacheFetch (
+  fetchParams,
+  isAuthenticationFetch = false,
+  isNewConnectionFetch = false
+) {
+  // 1. Let request be fetchParams’s request.
+  const request = fetchParams.request
+
+  // 2. Let httpFetchParams be null.
+  let httpFetchParams = null
+
+  // 3. Let httpRequest be null.
+  let httpRequest = null
+
+  // 4. Let response be null.
+  let response = null
+
+  // 5. Let storedResponse be null.
+  // TODO: cache
+
+  // 6. Let httpCache be null.
+  const httpCache = null
+
+  // 7. Let the revalidatingFlag be unset.
+  const revalidatingFlag = false
+
+  // 8. Run these steps, but abort when the ongoing fetch is terminated:
+
+  //    1. If request’s window is "no-window" and request’s redirect mode is
+  //    "error", then set httpFetchParams to fetchParams and httpRequest to
+  //    request.
+  if (request.window === 'no-window' && request.redirect === 'error') {
+    httpFetchParams = fetchParams
+    httpRequest = request
+  } else {
+    // Otherwise:
+
+    // 1. Set httpRequest to a clone of request.
+    httpRequest = cloneRequest(request)
+
+    // 2. Set httpFetchParams to a copy of fetchParams.
+    httpFetchParams = { ...fetchParams }
+
+    // 3. Set httpFetchParams’s request to httpRequest.
+    httpFetchParams.request = httpRequest
+  }
+
+  //    3. Let includeCredentials be true if one of
+  const includeCredentials =
+    request.credentials === 'include' ||
+    (request.credentials === 'same-origin' &&
+      request.responseTainting === 'basic')
+
+  //    4. Let contentLength be httpRequest’s body’s length, if httpRequest’s
+  //    body is non-null; otherwise null.
+  const contentLength = httpRequest.body ? httpRequest.body.length : null
+
+  //    5. Let contentLengthHeaderValue be null.
+  let contentLengthHeaderValue = null
+
+  //    6. If httpRequest’s body is null and httpRequest’s method is `POST` or
+  //    `PUT`, then set contentLengthHeaderValue to `0`.
+  if (
+    httpRequest.body == null &&
+    ['POST', 'PUT'].includes(httpRequest.method)
+  ) {
+    contentLengthHeaderValue = '0'
+  }
+
+  //    7. If contentLength is non-null, then set contentLengthHeaderValue to
+  //    contentLength, serialized and isomorphic encoded.
+  if (contentLength != null) {
+    contentLengthHeaderValue = isomorphicEncode(`${contentLength}`)
+  }
+
+  //    8. If contentLengthHeaderValue is non-null, then append
+  //    `Content-Length`/contentLengthHeaderValue to httpRequest’s header
+  //    list.
+  if (contentLengthHeaderValue != null) {
+    httpRequest.headersList.append('content-length', contentLengthHeaderValue, true)
+  }
+
+  //    9. If contentLengthHeaderValue is non-null, then append (`Content-Length`,
+  //    contentLengthHeaderValue) to httpRequest’s header list.
+
+  //    10. If contentLength is non-null and httpRequest’s keepalive is true,
+  //    then:
+  if (contentLength != null && httpRequest.keepalive) {
+    // NOTE: keepalive is a noop outside of browser context.
+  }
+
+  //    11. If httpRequest’s referrer is a URL, then append
+  //    `Referer`/httpRequest’s referrer, serialized and isomorphic encoded,
+  //     to httpRequest’s header list.
+  if (webidl.is.URL(httpRequest.referrer)) {
+    httpRequest.headersList.append('referer', isomorphicEncode(httpRequest.referrer.href), true)
+  }
+
+  //    12. Append a request `Origin` header for httpRequest.
+  appendRequestOriginHeader(httpRequest)
+
+  //    13. Append the Fetch metadata headers for httpRequest. [FETCH-METADATA]
+  appendFetchMetadata(httpRequest)
+
+  //    14. If httpRequest’s header list does not contain `User-Agent`, then
+  //    user agents should append `User-Agent`/default `User-Agent` value to
+  //    httpRequest’s header list.
+  if (!httpRequest.headersList.contains('user-agent', true)) {
+    httpRequest.headersList.append('user-agent', defaultUserAgent, true)
+  }
+
+  //    15. If httpRequest’s cache mode is "default" and httpRequest’s header
+  //    list contains `If-Modified-Since`, `If-None-Match`,
+  //    `If-Unmodified-Since`, `If-Match`, or `If-Range`, then set
+  //    httpRequest’s cache mode to "no-store".
+  if (
+    httpRequest.cache === 'default' &&
+    (httpRequest.headersList.contains('if-modified-since', true) ||
+      httpRequest.headersList.contains('if-none-match', true) ||
+      httpRequest.headersList.contains('if-unmodified-since', true) ||
+      httpRequest.headersList.contains('if-match', true) ||
+      httpRequest.headersList.contains('if-range', true))
+  ) {
+    httpRequest.cache = 'no-store'
+  }
+
+  //    16. If httpRequest’s cache mode is "no-cache", httpRequest’s prevent
+  //    no-cache cache-control header modification flag is unset, and
+  //    httpRequest’s header list does not contain `Cache-Control`, then append
+  //    `Cache-Control`/`max-age=0` to httpRequest’s header list.
+  if (
+    httpRequest.cache === 'no-cache' &&
+    !httpRequest.preventNoCacheCacheControlHeaderModification &&
+    !httpRequest.headersList.contains('cache-control', true)
+  ) {
+    httpRequest.headersList.append('cache-control', 'max-age=0', true)
+  }
+
+  //    17. If httpRequest’s cache mode is "no-store" or "reload", then:
+  if (httpRequest.cache === 'no-store' || httpRequest.cache === 'reload') {
+    // 1. If httpRequest’s header list does not contain `Pragma`, then append
+    // `Pragma`/`no-cache` to httpRequest’s header list.
+    if (!httpRequest.headersList.contains('pragma', true)) {
+      httpRequest.headersList.append('pragma', 'no-cache', true)
+    }
+
+    // 2. If httpRequest’s header list does not contain `Cache-Control`,
+    // then append `Cache-Control`/`no-cache` to httpRequest’s header list.
+    if (!httpRequest.headersList.contains('cache-control', true)) {
+      httpRequest.headersList.append('cache-control', 'no-cache', true)
+    }
+  }
+
+  //    18. If httpRequest’s header list contains `Range`, then append
+  //    `Accept-Encoding`/`identity` to httpRequest’s header list.
+  if (httpRequest.headersList.contains('range', true)) {
+    httpRequest.headersList.append('accept-encoding', 'identity', true)
+  }
+
+  //    19. Modify httpRequest’s header list per HTTP. Do not append a given
+  //    header if httpRequest’s header list contains that header’s name.
+  //    TODO: https://github.com/whatwg/fetch/issues/1285#issuecomment-896560129
+  if (!httpRequest.headersList.contains('accept-encoding', true)) {
+    if (urlHasHttpsScheme(requestCurrentURL(httpRequest))) {
+      httpRequest.headersList.append('accept-encoding', 'br, gzip, deflate', true)
+    } else {
+      httpRequest.headersList.append('accept-encoding', 'gzip, deflate', true)
+    }
+  }
+
+  httpRequest.headersList.delete('host', true)
+
+  //    21. If includeCredentials is true, then:
+  if (includeCredentials) {
+    // 1. If the user agent is not configured to block cookies for httpRequest
+    // (see section 7 of [COOKIES]), then:
+    // TODO: credentials
+
+    // 2. If httpRequest’s header list does not contain `Authorization`, then:
+    if (!httpRequest.headersList.contains('authorization', true)) {
+      // 1. Let authorizationValue be null.
+      let authorizationValue = null
+
+      // 2. If there’s an authentication entry for httpRequest and either
+      //    httpRequest’s use-URL-credentials flag is unset or httpRequest’s
+      //    current URL does not include credentials, then set
+      //    authorizationValue to authentication entry.
+      if (hasAuthenticationEntry(httpRequest) && (
+        httpRequest.useURLCredentials === undefined || !includesCredentials(requestCurrentURL(httpRequest))
+      )) {
+        // TODO
+      } else if (includesCredentials(requestCurrentURL(httpRequest)) && isAuthenticationFetch) {
+        // 3. Otherwise, if httpRequest’s current URL does include credentials
+        //    and isAuthenticationFetch is true, set authorizationValue to
+        //    httpRequest’s current URL, converted to an `Authorization` value
+        const { username, password } = requestCurrentURL(httpRequest)
+        authorizationValue = `Basic ${Buffer.from(`${username}:${password}`).toString('base64')}`
+      }
+
+      // 4. If authorizationValue is non-null, then append (`Authorization`,
+      //    authorizationValue) to httpRequest’s header list.
+      if (authorizationValue !== null) {
+        httpRequest.headersList.append('Authorization', authorizationValue, false)
+      }
+    }
+  }
+
+  //    21. If there’s a proxy-authentication entry, use it as appropriate.
+  //    TODO: proxy-authentication
+
+  //    22. Set httpCache to the result of determining the HTTP cache
+  //    partition, given httpRequest.
+  //    TODO: cache
+
+  //    23. If httpCache is null, then set httpRequest’s cache mode to
+  //    "no-store".
+  if (httpCache == null) {
+    httpRequest.cache = 'no-store'
+  }
+
+  //    24. If httpRequest’s cache mode is neither "no-store" nor "reload",
+  //    then:
+  if (httpRequest.cache !== 'no-store' && httpRequest.cache !== 'reload') {
+    // TODO: cache
+  }
+
+  // 9. If aborted, then return the appropriate network error for fetchParams.
+  // TODO
+
+  // 10. If response is null, then:
+  if (response == null) {
+    // 1. If httpRequest’s cache mode is "only-if-cached", then return a
+    // network error.
+    if (httpRequest.cache === 'only-if-cached') {
+      return makeNetworkError('only if cached')
+    }
+
+    // 2. Let forwardResponse be the result of running HTTP-network fetch
+    // given httpFetchParams, includeCredentials, and isNewConnectionFetch.
+    const forwardResponse = await httpNetworkFetch(
+      httpFetchParams,
+      includeCredentials,
+      isNewConnectionFetch
+    )
+
+    // 3. If httpRequest’s method is unsafe and forwardResponse’s status is
+    // in the range 200 to 399, inclusive, invalidate appropriate stored
+    // responses in httpCache, as per the "Invalidation" chapter of HTTP
+    // Caching, and set storedResponse to null. [HTTP-CACHING]
+    if (
+      !safeMethodsSet.has(httpRequest.method) &&
+      forwardResponse.status >= 200 &&
+      forwardResponse.status <= 399
+    ) {
+      // TODO: cache
+    }
+
+    // 4. If the revalidatingFlag is set and forwardResponse’s status is 304,
+    // then:
+    if (revalidatingFlag && forwardResponse.status === 304) {
+      // TODO: cache
+    }
+
+    // 5. If response is null, then:
+    if (response == null) {
+      // 1. Set response to forwardResponse.
+      response = forwardResponse
+
+      // 2. Store httpRequest and forwardResponse in httpCache, as per the
+      // "Storing Responses in Caches" chapter of HTTP Caching. [HTTP-CACHING]
+      // TODO: cache
+    }
+  }
+
+  // 11. Set response’s URL list to a clone of httpRequest’s URL list.
+  response.urlList = [...httpRequest.urlList]
+
+  // 12. If httpRequest’s header list contains `Range`, then set response’s
+  // range-requested flag.
+  if (httpRequest.headersList.contains('range', true)) {
+    response.rangeRequested = true
+  }
+
+  // 13. Set response’s request-includes-credentials to includeCredentials.
+  response.requestIncludesCredentials = includeCredentials
+
+  // 14. If response’s status is 401, httpRequest’s response tainting is not "cors",
+  //     includeCredentials is true, and request’s traversable for user prompts is
+  //     a traversable navigable:
+  if (response.status === 401 && httpRequest.responseTainting !== 'cors' && includeCredentials && isTraversableNavigable(request.traversableForUserPrompts)) {
+    // 2. If request’s body is non-null, then:
+    if (request.body != null) {
+      // 1. If request’s body’s source is null, then return a network error.
+      if (request.body.source == null) {
+        return makeNetworkError('expected non-null body source')
+      }
+
+      // 2. Set request’s body to the body of the result of safely extracting
+      //    request’s body’s source.
+      request.body = safelyExtractBody(request.body.source)[0]
+    }
+
+    // 3. If request’s use-URL-credentials flag is unset or isAuthenticationFetch is
+    //    true, then:
+    if (request.useURLCredentials === undefined || isAuthenticationFetch) {
+      // 1. If fetchParams is canceled, then return the appropriate network error
+      //    for fetchParams.
+      if (isCancelled(fetchParams)) {
+        return makeAppropriateNetworkError(fetchParams)
+      }
+
+      // 2. Let username and password be the result of prompting the end user for a
+      //    username and password, respectively, in request’s traversable for user prompts.
+      // TODO
+
+      // 3. Set the username given request’s current URL and username.
+      // requestCurrentURL(request).username = TODO
+
+      // 4. Set the password given request’s current URL and password.
+      // requestCurrentURL(request).password = TODO
+
+      // In browsers, the user will be prompted to enter a username/password before the request
+      // is re-sent. To prevent an infinite 401 loop, return the response for now.
+      // https://github.com/nodejs/undici/pull/4756
+      return response
+    }
+
+    // 4. Set response to the result of running HTTP-network-or-cache fetch given
+    //    fetchParams and true.
+    fetchParams.controller.connection.destroy()
+
+    response = await httpNetworkOrCacheFetch(fetchParams, true)
+  }
+
+  // 15. If response’s status is 407, then:
+  if (response.status === 407) {
+    // 1. If request’s window is "no-window", then return a network error.
+    if (request.window === 'no-window') {
+      return makeNetworkError()
+    }
+
+    // 2. ???
+
+    // 3. If fetchParams is canceled, then return the appropriate network error for fetchParams.
+    if (isCancelled(fetchParams)) {
+      return makeAppropriateNetworkError(fetchParams)
+    }
+
+    // 4. Prompt the end user as appropriate in request’s window and store
+    // the result as a proxy-authentication entry. [HTTP-AUTH]
+    // TODO: Invoke some kind of callback?
+
+    // 5. Set response to the result of running HTTP-network-or-cache fetch given
+    // fetchParams.
+    // TODO
+    return makeNetworkError('proxy authentication required')
+  }
+
+  // 16. If all of the following are true
+  if (
+    // response’s status is 421
+    response.status === 421 &&
+    // isNewConnectionFetch is false
+    !isNewConnectionFetch &&
+    // request’s body is null, or request’s body is non-null and request’s body’s source is non-null
+    (request.body == null || request.body.source != null)
+  ) {
+    // then:
+
+    // 1. If fetchParams is canceled, then return the appropriate network error for fetchParams.
+    if (isCancelled(fetchParams)) {
+      return makeAppropriateNetworkError(fetchParams)
+    }
+
+    // 2. Set response to the result of running HTTP-network-or-cache
+    // fetch given fetchParams, isAuthenticationFetch, and true.
+
+    // TODO (spec): The spec doesn't specify this but we need to cancel
+    // the active response before we can start a new one.
+    // https://github.com/whatwg/fetch/issues/1293
+    fetchParams.controller.connection.destroy()
+
+    response = await httpNetworkOrCacheFetch(
+      fetchParams,
+      isAuthenticationFetch,
+      true
+    )
+  }
+
+  // 17. If isAuthenticationFetch is true, then create an authentication entry
+  if (isAuthenticationFetch) {
+    // TODO
+  }
+
+  // 18. Return response.
+  return response
+}
+
+// https://fetch.spec.whatwg.org/#http-network-fetch
+async function httpNetworkFetch (
+  fetchParams,
+  includeCredentials = false,
+  forceNewConnection = false
+) {
+  assert(!fetchParams.controller.connection || fetchParams.controller.connection.destroyed)
+
+  fetchParams.controller.connection = {
+    abort: null,
+    destroyed: false,
+    destroy (err, abort = true) {
+      if (!this.destroyed) {
+        this.destroyed = true
+        if (abort) {
+          this.abort?.(err ?? new DOMException('The operation was aborted.', 'AbortError'))
+        }
+      }
+    }
+  }
+
+  // 1. Let request be fetchParams’s request.
+  const request = fetchParams.request
+
+  // 2. Let response be null.
+  let response = null
+
+  // 3. Let timingInfo be fetchParams’s timing info.
+  const timingInfo = fetchParams.timingInfo
+
+  // 4. Let httpCache be the result of determining the HTTP cache partition,
+  // given request.
+  // TODO: cache
+  const httpCache = null
+
+  // 5. If httpCache is null, then set request’s cache mode to "no-store".
+  if (httpCache == null) {
+    request.cache = 'no-store'
+  }
+
+  // 6. Let networkPartitionKey be the result of determining the network
+  // partition key given request.
+  // TODO
+
+  // 7. Let newConnection be "yes" if forceNewConnection is true; otherwise
+  // "no".
+  const newConnection = forceNewConnection ? 'yes' : 'no' // eslint-disable-line no-unused-vars
+
+  // 8. Switch on request’s mode:
+  if (request.mode === 'websocket') {
+    // Let connection be the result of obtaining a WebSocket connection,
+    // given request’s current URL.
+    // TODO
+  } else {
+    // Let connection be the result of obtaining a connection, given
+    // networkPartitionKey, request’s current URL’s origin,
+    // includeCredentials, and forceNewConnection.
+    // TODO
+  }
+
+  // 9. Run these steps, but abort when the ongoing fetch is terminated:
+
+  //    1. If connection is failure, then return a network error.
+
+  //    2. Set timingInfo’s final connection timing info to the result of
+  //    calling clamp and coarsen connection timing info with connection’s
+  //    timing info, timingInfo’s post-redirect start time, and fetchParams’s
+  //    cross-origin isolated capability.
+
+  //    3. If connection is not an HTTP/2 connection, request’s body is non-null,
+  //    and request’s body’s source is null, then append (`Transfer-Encoding`,
+  //    `chunked`) to request’s header list.
+
+  //    4. Set timingInfo’s final network-request start time to the coarsened
+  //    shared current time given fetchParams’s cross-origin isolated
+  //    capability.
+
+  //    5. Set response to the result of making an HTTP request over connection
+  //    using request with the following caveats:
+
+  //        - Follow the relevant requirements from HTTP. [HTTP] [HTTP-SEMANTICS]
+  //        [HTTP-COND] [HTTP-CACHING] [HTTP-AUTH]
+
+  //        - If request’s body is non-null, and request’s body’s source is null,
+  //        then the user agent may have a buffer of up to 64 kibibytes and store
+  //        a part of request’s body in that buffer. If the user agent reads from
+  //        request’s body beyond that buffer’s size and the user agent needs to
+  //        resend request, then instead return a network error.
+
+  //        - Set timingInfo’s final network-response start time to the coarsened
+  //        shared current time given fetchParams’s cross-origin isolated capability,
+  //        immediately after the user agent’s HTTP parser receives the first byte
+  //        of the response (e.g., frame header bytes for HTTP/2 or response status
+  //        line for HTTP/1.x).
+
+  //        - Wait until all the headers are transmitted.
+
+  //        - Any responses whose status is in the range 100 to 199, inclusive,
+  //        and is not 101, are to be ignored, except for the purposes of setting
+  //        timingInfo’s final network-response start time above.
+
+  //    - If request’s header list contains `Transfer-Encoding`/`chunked` and
+  //    response is transferred via HTTP/1.0 or older, then return a network
+  //    error.
+
+  //    - If the HTTP request results in a TLS client certificate dialog, then:
+
+  //        1. If request’s window is an environment settings object, make the
+  //        dialog available in request’s window.
+
+  //        2. Otherwise, return a network error.
+
+  // To transmit request’s body body, run these steps:
+  let requestBody = null
+  // 1. If body is null and fetchParams’s process request end-of-body is
+  // non-null, then queue a fetch task given fetchParams’s process request
+  // end-of-body and fetchParams’s task destination.
+  if (request.body == null && fetchParams.processRequestEndOfBody) {
+    queueMicrotask(() => fetchParams.processRequestEndOfBody())
+  } else if (request.body != null) {
+    // 2. Otherwise, if body is non-null:
+
+    //    1. Let processBodyChunk given bytes be these steps:
+    const processBodyChunk = async function * (bytes) {
+      // 1. If the ongoing fetch is terminated, then abort these steps.
+      if (isCancelled(fetchParams)) {
+        return
+      }
+
+      // 2. Run this step in parallel: transmit bytes.
+      yield bytes
+
+      // 3. If fetchParams’s process request body is non-null, then run
+      // fetchParams’s process request body given bytes’s length.
+      fetchParams.processRequestBodyChunkLength?.(bytes.byteLength)
+    }
+
+    // 2. Let processEndOfBody be these steps:
+    const processEndOfBody = () => {
+      // 1. If fetchParams is canceled, then abort these steps.
+      if (isCancelled(fetchParams)) {
+        return
+      }
+
+      // 2. If fetchParams’s process request end-of-body is non-null,
+      // then run fetchParams’s process request end-of-body.
+      if (fetchParams.processRequestEndOfBody) {
+        fetchParams.processRequestEndOfBody()
+      }
+    }
+
+    // 3. Let processBodyError given e be these steps:
+    const processBodyError = (e) => {
+      // 1. If fetchParams is canceled, then abort these steps.
+      if (isCancelled(fetchParams)) {
+        return
+      }
+
+      // 2. If e is an "AbortError" DOMException, then abort fetchParams’s controller.
+      if (e.name === 'AbortError') {
+        fetchParams.controller.abort()
+      } else {
+        fetchParams.controller.terminate(e)
+      }
+    }
+
+    // 4. Incrementally read request’s body given processBodyChunk, processEndOfBody,
+    // processBodyError, and fetchParams’s task destination.
+    requestBody = (async function * () {
+      try {
+        for await (const bytes of request.body.stream) {
+          yield * processBodyChunk(bytes)
+        }
+        processEndOfBody()
+      } catch (err) {
+        processBodyError(err)
+      }
+    })()
+  }
+
+  try {
+    // socket is only provided for websockets
+    const { body, status, statusText, headersList, socket } = await dispatch({ body: requestBody })
+
+    if (socket) {
+      response = makeResponse({ status, statusText, headersList, socket })
+    } else {
+      const iterator = body[Symbol.asyncIterator]()
+      fetchParams.controller.next = () => iterator.next()
+
+      response = makeResponse({ status, statusText, headersList })
+    }
+  } catch (err) {
+    // 10. If aborted, then:
+    if (err.name === 'AbortError') {
+      // 1. If connection uses HTTP/2, then transmit an RST_STREAM frame.
+      fetchParams.controller.connection.destroy()
+
+      // 2. Return the appropriate network error for fetchParams.
+      return makeAppropriateNetworkError(fetchParams, err)
+    }
+
+    return makeNetworkError(err)
+  }
+
+  // 11. Let pullAlgorithm be an action that resumes the ongoing fetch
+  // if it is suspended.
+  const pullAlgorithm = () => {
+    return fetchParams.controller.resume()
+  }
+
+  // 12. Let cancelAlgorithm be an algorithm that aborts fetchParams’s
+  // controller with reason, given reason.
+  const cancelAlgorithm = (reason) => {
+    // If the aborted fetch was already terminated, then we do not
+    // need to do anything.
+    if (!isCancelled(fetchParams)) {
+      fetchParams.controller.abort(reason)
+    }
+  }
+
+  // 13. Let highWaterMark be a non-negative, non-NaN number, chosen by
+  // the user agent.
+  // TODO
+
+  // 14. Let sizeAlgorithm be an algorithm that accepts a chunk object
+  // and returns a non-negative, non-NaN, non-infinite number, chosen by the user agent.
+  // TODO
+
+  // 15. Let stream be a new ReadableStream.
+  // 16. Set up stream with byte reading support with pullAlgorithm set to pullAlgorithm,
+  //     cancelAlgorithm set to cancelAlgorithm.
+  const stream = new ReadableStream(
+    {
+      start (controller) {
+        fetchParams.controller.controller = controller
+      },
+      pull: pullAlgorithm,
+      cancel: cancelAlgorithm,
+      type: 'bytes'
+    }
+  )
+
+  // 17. Run these steps, but abort when the ongoing fetch is terminated:
+
+  //    1. Set response’s body to a new body whose stream is stream.
+  response.body = { stream, source: null, length: null }
+
+  //    2. If response is not a network error and request’s cache mode is
+  //    not "no-store", then update response in httpCache for request.
+  //    TODO
+
+  //    3. If includeCredentials is true and the user agent is not configured
+  //    to block cookies for request (see section 7 of [COOKIES]), then run the
+  //    "set-cookie-string" parsing algorithm (see section 5.2 of [COOKIES]) on
+  //    the value of each header whose name is a byte-case-insensitive match for
+  //    `Set-Cookie` in response’s header list, if any, and request’s current URL.
+  //    TODO
+
+  // 18. If aborted, then:
+  // TODO
+
+  // 19. Run these steps in parallel:
+
+  //    1. Run these steps, but abort when fetchParams is canceled:
+  if (!fetchParams.controller.resume) {
+    fetchParams.controller.on('terminated', onAborted)
+  }
+
+  fetchParams.controller.resume = async () => {
+    // 1. While true
+    while (true) {
+      // 1-3. See onData...
+
+      // 4. Set bytes to the result of handling content codings given
+      // codings and bytes.
+      let bytes
+      let isFailure
+      try {
+        const { done, value } = await fetchParams.controller.next()
+
+        if (isAborted(fetchParams)) {
+          break
+        }
+
+        bytes = done ? undefined : value
+      } catch (err) {
+        if (fetchParams.controller.ended && !timingInfo.encodedBodySize) {
+          // zlib doesn't like empty streams.
+          bytes = undefined
+        } else {
+          bytes = err
+
+          // err may be propagated from the result of calling readablestream.cancel,
+          // which might not be an error. https://github.com/nodejs/undici/issues/2009
+          isFailure = true
+        }
+      }
+
+      if (bytes === undefined) {
+        // 2. Otherwise, if the bytes transmission for response’s message
+        // body is done normally and stream is readable, then close
+        // stream, finalize response for fetchParams and response, and
+        // abort these in-parallel steps.
+        readableStreamClose(fetchParams.controller.controller)
+
+        finalizeResponse(fetchParams, response)
+
+        return
+      }
+
+      // 5. Increase timingInfo’s decoded body size by bytes’s length.
+      timingInfo.decodedBodySize += bytes?.byteLength ?? 0
+
+      // 6. If bytes is failure, then terminate fetchParams’s controller.
+      if (isFailure) {
+        fetchParams.controller.terminate(bytes)
+        return
+      }
+
+      // 7. Enqueue a Uint8Array wrapping an ArrayBuffer containing bytes
+      // into stream.
+      const buffer = new Uint8Array(bytes)
+      if (buffer.byteLength) {
+        fetchParams.controller.controller.enqueue(buffer)
+      }
+
+      // 8. If stream is errored, then terminate the ongoing fetch.
+      if (isErrored(stream)) {
+        fetchParams.controller.terminate()
+        return
+      }
+
+      // 9. If stream doesn’t need more data ask the user agent to suspend
+      // the ongoing fetch.
+      if (fetchParams.controller.controller.desiredSize <= 0) {
+        return
+      }
+    }
+  }
+
+  //    2. If aborted, then:
+  function onAborted (reason) {
+    // 2. If fetchParams is aborted, then:
+    if (isAborted(fetchParams)) {
+      // 1. Set response’s aborted flag.
+      response.aborted = true
+
+      // 2. If stream is readable, then error stream with the result of
+      //    deserialize a serialized abort reason given fetchParams’s
+      //    controller’s serialized abort reason and an
+      //    implementation-defined realm.
+      if (isReadable(stream)) {
+        fetchParams.controller.controller.error(
+          fetchParams.controller.serializedAbortReason
+        )
+      }
+    } else {
+      // 3. Otherwise, if stream is readable, error stream with a TypeError.
+      if (isReadable(stream)) {
+        fetchParams.controller.controller.error(new TypeError('terminated', {
+          cause: isErrorLike(reason) ? reason : undefined
+        }))
+      }
+    }
+
+    // 4. If connection uses HTTP/2, then transmit an RST_STREAM frame.
+    // 5. Otherwise, the user agent should close connection unless it would be bad for performance to do so.
+    fetchParams.controller.connection.destroy()
+  }
+
+  // 20. Return response.
+  return response
+
+  function dispatch ({ body }) {
+    const url = requestCurrentURL(request)
+    /** @type {import('../../..').Agent} */
+    const agent = fetchParams.controller.dispatcher
+
+    return new Promise((resolve, reject) => agent.dispatch(
+      {
+        path: url.pathname + url.search,
+        origin: url.origin,
+        method: request.method,
+        body: agent.isMockActive ? request.body && (request.body.source || request.body.stream) : body,
+        headers: request.headersList.entries,
+        maxRedirections: 0,
+        upgrade: request.mode === 'websocket' ? 'websocket' : undefined
+      },
+      {
+        body: null,
+        abort: null,
+
+        onConnect (abort) {
+          // TODO (fix): Do we need connection here?
+          const { connection } = fetchParams.controller
+
+          // Set timingInfo’s final connection timing info to the result of calling clamp and coarsen
+          // connection timing info with connection’s timing info, timingInfo’s post-redirect start
+          // time, and fetchParams’s cross-origin isolated capability.
+          // TODO: implement connection timing
+          timingInfo.finalConnectionTimingInfo = clampAndCoarsenConnectionTimingInfo(undefined, timingInfo.postRedirectStartTime, fetchParams.crossOriginIsolatedCapability)
+
+          if (connection.destroyed) {
+            abort(new DOMException('The operation was aborted.', 'AbortError'))
+          } else {
+            fetchParams.controller.on('terminated', abort)
+            this.abort = connection.abort = abort
+          }
+
+          // Set timingInfo’s final network-request start time to the coarsened shared current time given
+          // fetchParams’s cross-origin isolated capability.
+          timingInfo.finalNetworkRequestStartTime = coarsenedSharedCurrentTime(fetchParams.crossOriginIsolatedCapability)
+        },
+
+        onResponseStarted () {
+          // Set timingInfo’s final network-response start time to the coarsened shared current
+          // time given fetchParams’s cross-origin isolated capability, immediately after the
+          // user agent’s HTTP parser receives the first byte of the response (e.g., frame header
+          // bytes for HTTP/2 or response status line for HTTP/1.x).
+          timingInfo.finalNetworkResponseStartTime = coarsenedSharedCurrentTime(fetchParams.crossOriginIsolatedCapability)
+        },
+
+        onHeaders (status, rawHeaders, resume, statusText) {
+          if (status < 200) {
+            return false
+          }
+
+          const headersList = new HeadersList()
+
+          for (let i = 0; i < rawHeaders.length; i += 2) {
+            headersList.append(bufferToLowerCasedHeaderName(rawHeaders[i]), rawHeaders[i + 1].toString('latin1'), true)
+          }
+          const location = headersList.get('location', true)
+
+          this.body = new Readable({ read: resume })
+
+          const willFollow = location && request.redirect === 'follow' &&
+            redirectStatusSet.has(status)
+
+          const decoders = []
+
+          // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Encoding
+          if (request.method !== 'HEAD' && request.method !== 'CONNECT' && !nullBodyStatus.includes(status) && !willFollow) {
+            // https://www.rfc-editor.org/rfc/rfc7231#section-3.1.2.1
+            const contentEncoding = headersList.get('content-encoding', true)
+            // "All content-coding values are case-insensitive..."
+            /** @type {string[]} */
+            const codings = contentEncoding ? contentEncoding.toLowerCase().split(',') : []
+
+            // Limit the number of content-encodings to prevent resource exhaustion.
+            // CVE fix similar to urllib3 (GHSA-gm62-xv2j-4w53) and curl (CVE-2022-32206).
+            const maxContentEncodings = 5
+            if (codings.length > maxContentEncodings) {
+              reject(new Error(`too many content-encodings in response: ${codings.length}, maximum allowed is ${maxContentEncodings}`))
+              return true
+            }
+
+            for (let i = codings.length - 1; i >= 0; --i) {
+              const coding = codings[i].trim()
+              // https://www.rfc-editor.org/rfc/rfc9112.html#section-7.2
+              if (coding === 'x-gzip' || coding === 'gzip') {
+                decoders.push(zlib.createGunzip({
+                  // Be less strict when decoding compressed responses, since sometimes
+                  // servers send slightly invalid responses that are still accepted
+                  // by common browsers.
+                  // Always using Z_SYNC_FLUSH is what cURL does.
+                  flush: zlib.constants.Z_SYNC_FLUSH,
+                  finishFlush: zlib.constants.Z_SYNC_FLUSH
+                }))
+              } else if (coding === 'deflate') {
+                decoders.push(createInflate({
+                  flush: zlib.constants.Z_SYNC_FLUSH,
+                  finishFlush: zlib.constants.Z_SYNC_FLUSH
+                }))
+              } else if (coding === 'br') {
+                decoders.push(zlib.createBrotliDecompress({
+                  flush: zlib.constants.BROTLI_OPERATION_FLUSH,
+                  finishFlush: zlib.constants.BROTLI_OPERATION_FLUSH
+                }))
+              } else if (coding === 'zstd' && hasZstd) {
+                decoders.push(zlib.createZstdDecompress({
+                  flush: zlib.constants.ZSTD_e_continue,
+                  finishFlush: zlib.constants.ZSTD_e_end
+                }))
+              } else {
+                decoders.length = 0
+                break
+              }
+            }
+          }
+
+          const onError = this.onError.bind(this)
+
+          resolve({
+            status,
+            statusText,
+            headersList,
+            body: decoders.length
+              ? pipeline(this.body, ...decoders, (err) => {
+                if (err) {
+                  this.onError(err)
+                }
+              }).on('error', onError)
+              : this.body.on('error', onError)
+          })
+
+          return true
+        },
+
+        onData (chunk) {
+          if (fetchParams.controller.dump) {
+            return
+          }
+
+          // 1. If one or more bytes have been transmitted from response’s
+          // message body, then:
+
+          //  1. Let bytes be the transmitted bytes.
+          const bytes = chunk
+
+          //  2. Let codings be the result of extracting header list values
+          //  given `Content-Encoding` and response’s header list.
+          //  See pullAlgorithm.
+
+          //  3. Increase timingInfo’s encoded body size by bytes’s length.
+          timingInfo.encodedBodySize += bytes.byteLength
+
+          //  4. See pullAlgorithm...
+
+          return this.body.push(bytes)
+        },
+
+        onComplete () {
+          if (this.abort) {
+            fetchParams.controller.off('terminated', this.abort)
+          }
+
+          fetchParams.controller.ended = true
+
+          this.body.push(null)
+        },
+
+        onError (error) {
+          if (this.abort) {
+            fetchParams.controller.off('terminated', this.abort)
+          }
+
+          this.body?.destroy(error)
+
+          fetchParams.controller.terminate(error)
+
+          reject(error)
+        },
+
+        onRequestUpgrade (_controller, status, headers, socket) {
+          // We need to support 200 for websocket over h2 as per RFC-8441
+          // Absence of session means H1
+          if ((socket.session != null && status !== 200) || (socket.session == null && status !== 101)) {
+            return false
+          }
+
+          const headersList = new HeadersList()
+
+          for (const [name, value] of Object.entries(headers)) {
+            if (value == null) {
+              continue
+            }
+
+            const headerName = name.toLowerCase()
+
+            if (Array.isArray(value)) {
+              for (const entry of value) {
+                headersList.append(headerName, String(entry), true)
+              }
+            } else {
+              headersList.append(headerName, String(value), true)
+            }
+          }
+
+          resolve({
+            status,
+            statusText: STATUS_CODES[status],
+            headersList,
+            socket
+          })
+
+          return true
+        },
+
+        onUpgrade (status, rawHeaders, socket) {
+          // We need to support 200 for websocket over h2 as per RFC-8441
+          // Absence of session means H1
+          if ((socket.session != null && status !== 200) || (socket.session == null && status !== 101)) {
+            return false
+          }
+
+          const headersList = new HeadersList()
+
+          for (let i = 0; i < rawHeaders.length; i += 2) {
+            headersList.append(bufferToLowerCasedHeaderName(rawHeaders[i]), rawHeaders[i + 1].toString('latin1'), true)
+          }
+
+          resolve({
+            status,
+            statusText: STATUS_CODES[status],
+            headersList,
+            socket
+          })
+
+          return true
+        }
+      }
+    ))
+  }
+}
+
+module.exports = {
+  fetch,
+  Fetch,
+  fetching,
+  finalizeAndReportTiming
+}