code: def _set_process_async(process):
      
      for fd in [process.stderr.fileno(), process.stdout.fileno()]:
          fl = fcntl.fcntl(fd, fcntl.F_GETFL)
          fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
docs: Make the process read/write methods unblocking