fix: use fasttimers for all connection timeouts

lib/dispatcher/client-h1.js

@@ -165,13 +165,9 @@ class Parser {
   setTimeout (delay, type) {
     this.timeoutType = type
     if (delay !== this.timeoutValue) {
-      this.timeout && timers.clearTimeout(this.timeout)
+      this.timeout && timers.clearFastTimeout(this.timeout)
       if (delay) {
-        this.timeout = timers.setTimeout(onParserTimeout, delay, new WeakRef(this))
-        // istanbul ignore else: only for jest
-        if (this.timeout.unref) {
-          this.timeout.unref()
-        }
+        this.timeout = timers.setFastTimeout(onParserTimeout, delay, new WeakRef(this))
       } else {
         this.timeout = null
       }

lib/util/timers.js

@@ -347,7 +347,7 @@ module.exports = {
    * The clearTimeout method cancels an instantiated Timer previously created
    * by calling setTimeout.
    *
-   * @param {FastTimer} timeout
+   * @param {NodeJS.Timeout|FastTimer} timeout
    */
   clearTimeout (timeout) {
     // If the timeout is a FastTimer, call its own clear method.
@@ -362,6 +362,31 @@ module.exports = {
       nativeClearTimeout(timeout)
     }
   },
+  /**
+   * The setFastTimeout() method sets a fastTimer which executes a function once
+   * the timer expires.
+   * @param {Function} callback A function to be executed after the timer
+   * expires.
+   * @param {number} delay The time, in milliseconds that the timer should
+   * wait before the specified function or code is executed.
+   * @param {*} [arg] An optional argument to be passed to the callback function
+   * when the timer expires.
+   * @returns {FastTimer}
+   */
+  setFastTimeout (callback, delay, arg) {
+    // If the delay is less than or equal to the RESOLUTION_MS value return a
+    // native Node.js Timer instance.
+    return new FastTimer(callback, delay, arg)
+  },
+  /**
+   * The clearTimeout method cancels an instantiated FastTimer previously
+   * created by calling setFastTimeout.
+   *
+   * @param {FastTimer} timeout
+   */
+  clearFastTimeout (timeout) {
+    timeout.clear()
+  },
   /**
    * The now method returns the value of the internal fast timer clock.
    *
@@ -370,6 +395,13 @@ module.exports = {
   now () {
     return fastNow
   },
+  /**
+   * Trigger the onTick function to process the fastTimers array.
+   * Exported for testing purposes only.
+   */
+  tick () {
+    onTick()
+  },
   /**
    * Exporting for testing purposes only.
    * Marking as deprecated to discourage any use outside of testing.

test/issue-3356.js

@@ -4,7 +4,7 @@ const { tspl } = require('@matteo.collina/tspl')
 const { test, after } = require('node:test')
 const { createServer } = require('node:http')
 const { once } = require('node:events')
-
+const { tick: fastTimerTick } = require('../lib/util/timers')
 const { fetch, Agent, RetryAgent } = require('..')
 
 test('https://github.com/nodejs/undici/issues/3356', async (t) => {
@@ -42,6 +42,10 @@ test('https://github.com/nodejs/undici/issues/3356', async (t) => {
   const response = await fetch(`http://localhost:${server.address().port}`, {
     dispatcher: agent
   })
+
+  fastTimerTick()
+  fastTimerTick()
+
   setTimeout(async () => {
     try {
       t.equal(response.status, 200)