perf (fetch): use less promises for ReadableStream

lib/core/util.js

@@ -609,12 +609,11 @@ function ReadableStreamFrom (iterable) {
   let iterator
   return new ReadableStream(
     {
-      async start () {
+      start () {
         iterator = iterable[Symbol.asyncIterator]()
       },
       pull (controller) {
-        async function pull () {
-          const { done, value } = await iterator.next()
+        return iterator.next().then(({ done, value }) => {
           if (done) {
             queueMicrotask(() => {
               controller.close()
@@ -625,15 +624,13 @@ function ReadableStreamFrom (iterable) {
             if (buf.byteLength) {
               controller.enqueue(new Uint8Array(buf))
             } else {
-              return await pull()
+              return this.pull(controller)
             }
           }
-        }
-
-        return pull()
+        })
       },
-      async cancel () {
-        await iterator.return()
+      cancel () {
+        return iterator.return()
       },
       type: 'bytes'
     }

test/fetch/issue-node-56474.js → test/fetch/readable-stream-from.js

@@ -1,7 +1,7 @@
 'use strict'
 
-const { test } = require('node:test')
 const { deepStrictEqual } = require('node:assert')
+const { test } = require('node:test')
 const { Response } = require('../..')
 
 // https://github.com/nodejs/node/issues/56474