Async iteration over tcp stream produces more chunks

Version

20.12, 22

Platform

Microsoft Windows NT 10.0.19045.0 x64

Subsystem

No response

What steps will reproduce the bug?

Below are two examples of code that read data from a TCP stream. In the first example, data is read using the for-await iteration approach, resulting in 2731 chunks. In contrast, the latest approach employs the stream.on('data') listener and retrieves 1835 chunks.

For-await listing:

import { createServer, Socket } from 'node:net'
import { Readable } from 'node:stream'

const server = createServer(socket => {
  const stream = Readable.from(numbers())
  stream.pipe(socket)
})
server.listen(3000, '127.0.0.1')

const client = new Socket()
client.connect(3000, '127.0.0.1')

const data = []
for await (const chunk of client) data.push(chunk)
console.log(data.length) // 2731 chunks
// console.table(data.map(({ length }) => length))
console.log(Buffer.concat(data).length)
client.destroy()
server.close()

async function* numbers (max = 10_000_000) {
  for (let i = 0; i < max; i++) yield i.toString()
}

event-based listing:

import { createServer, Socket } from 'node:net'
import { Readable } from 'node:stream'

const server = createServer(socket => {
  const stream = Readable.from(numbers())
  stream.pipe(socket)
})
server.listen(3000, '127.0.0.1')

const client = new Socket()
client.connect(3000, '127.0.0.1')

const data = []
client.on('data', chunk => data.push(chunk))
client.on('end', () => {
  console.log(data.length) // 1835 chunks
  // console.table(data.map(({ length }) => length))
  console.log(Buffer.concat(data).length)
  client.destroy()
  server.close()
})

async function* numbers (max = 10_000_000) {
  for (let i = 0; i < max; i++) yield i.toString()
}

How often does it reproduce? Is there a required condition?

Always

What is the expected behavior? Why is that the expected behavior?

Both for-await and on('data') should produce equal number of chunks.

What do you see instead?

for-await produce more chunks

Additional information