node:fs createWriteStream - IO blocks event loop

[nesterow]

What version of Bun is running?

1.1.30

What platform is your computer?

Darwin 23.6.0 arm64 arm

What steps can reproduce the bug?

When piping to a file (fs.createWriteStream) the IO blocks event loop. For example, the timers become unresponsive.
Following code uses two streams. Readable - generates some chunks, fs WriteStream is supposed to write them to a file.
For example I use a setInterval which prints some stats every second and a setTimeout for some delayed task.

import { Readable } from "node:stream";
import { createWriteStream } from "node:fs";

function* generate(sizeMb = 512) {
  let size = 0;
  while (size <= sizeMb * 1024 ** 2) {
    const data = new Array(64).fill("X").join("");
    size += data.length;
    yield data;
  }
}

// use stream to generate some bytes
const Iterator = generate();
let readBytes = 0;
const reader = new Readable({
  objectMode: false,
  read(size) {
    const data = Iterator.next();
    if (data.done) {
      return this.push(null);
    }
    readBytes += data.value.length;
    this.push(data.value);
  },
});

// write to file
const file = createWriteStream("fake.data.txt");
reader.pipe(file);
reader.once("close", () => {
  clearInterval(interval);
  stats(readBytes);
  console.log("🟩 finished writing file");
});

// print stats
const interval = setInterval(() => stats(readBytes), 1000);

setTimeout(() => {
  console.log("⚠️ Some dealyed task");
});

const stats = (written: number) => {
  console.log(
    "💾 saved ",
    Math.round(written / 1024 / 1024),
    "MB;",
    "📈 RSS:",
    Math.round(process.memoryUsage().rss / 1024 / 1024),
    "MB",
  );
};

console.log("🔁 started writing file");

What is the expected behavior?

Expected the timers to work while performing IO. Deno/Node output:

deno -A write-file.ts

🔁 started writing file
⚠️ Some dealyed task
💾 saved  65 MB; 📈 RSS: 85 MB
💾 saved  134 MB; 📈 RSS: 85 MB
💾 saved  202 MB; 📈 RSS: 85 MB
💾 saved  271 MB; 📈 RSS: 85 MB
💾 saved  338 MB; 📈 RSS: 85 MB
💾 saved  405 MB; 📈 RSS: 85 MB
💾 saved  473 MB; 📈 RSS: 85 MB
💾 saved  512 MB; 📈 RSS: 85 MB
🟩 finished writing file

What do you see instead?

Bun starts the timers after the write stream is closed. Which is practically fs.writeFileSync:

bun write-file.ts

🔁 started writing file
💾 saved  512 MB; 📈 RSS: 83 MB
🟩 finished writing file
⚠️ Some dealyed task

Additional information

No response