How to substitute BunFile for node:fs/promises.open?

[guest271314]

I have some working Node.js code https://github.com/guest271314/native-messaging-nodejs/blob/main/nm_nodejs.js to asynchronously read stdin and write to stdout. In pertinent part

import { open } from "node:fs/promises";

async function readFullAsync(length, buffer = new Uint8Array(65536)) {
  const data = [];
  while (data.length < length) {
    const input = await open("/dev/stdin");
    let { bytesRead } = await input.read({
      buffer
    });
    await input.close();
    if (bytesRead === 0) {
      break;
    }
    data.push(...buffer.subarray(0, bytesRead));  
  }
  return new Uint8Array(data);
}

async function getMessage() {
  const header = new Uint32Array(1);
  await readFullAsync(1, header);
  const content = await readFullAsync(header[0]);
  return content;
}

async function sendMessage(message) {
  const header = new Uint32Array([message.length]);
  const stdout = await open("/proc/self/fd/1", "w");
  await stdout.write(header);
  await stdout.write(message);
  await stdout.close();
  global.gc();
}

Reading https://bun.sh/docs/runtime/nodejs-apis

fs.promises.open incorrectly returns a file descriptor instead of a FileHandle.

I can't use Node.js open() and get the same result.