Conn.write and concurent buffer mutation

[exe-dealer]

Is it ok to mutate buffer after it was passed to conn.write without awaiting conn.write ?
I made simple test and got no broken bytes in case of concurent buffer mutation.

// expect dots (.) in stdout if concurent buffer mutation breaks conn.write behavior
// otherwise expect all Os

// public tcp echo server
const conn = await Deno.connect({ hostname: 'tcpbin.com', port: 4242 });

await Promise.all([
  Deno.copy(conn, Deno.stdout),
  write(),
]);


async function write() {
  const buf = new Uint8Array(81);
  buf[80] = 10; // \n
  for (let i = 0; i < 1000; i++) {
    buf.fill(79/*O*/, 0, 80);
    await Promise.all([
      // if buffer is not fully written than
      // line will be different length than other,
      // so we can see that and repeat test
      conn.write(buf),

      // mutate buffer concurently
      buf.fill(46/*.*/, 0, 80),
    ]);
  }
  await conn.closeWrite();
}