pid int
}

// result is the return value of a Read or Write operation.
type result struct {
	n   int
	err error
}

// newAsyncIO returns a new asyncIO that performs an I/O
// operation by calling fn, which must do one and only one
// interruptible system call.
func newAsyncIO(fn func([]byte) (int, error), b []byte) *asyncIO {
	aio := &asyncIO{
		res: make(chan result, 0),
	}
	aio.mu.Lock()
	go func() {

		return 0, err
	}
	defer fd.readUnlock()
	if len(b) == 0 {
		return 0, nil
	}
	fd.rmu.Lock()
	if fd.rtimedout {
		fd.rmu.Unlock()
		return 0, ErrDeadlineExceeded
	}
	fd.raio = newAsyncIO(fn, b)
	fd.rmu.Unlock()
	n, err := fd.raio.Wait()
	fd.raio = nil
	if isHangup(err) {
		err = io.EOF
	}
	if isInterrupted(err) {
		err = ErrDeadlineExceeded
	}
	return n, err
}