code: func newOverlapped() (*syscall.Overlapped, error) {
  	event, err := createEvent(nil, true, true, nil)
  	if err != nil {
  		return nil, err
  	}
  	return &syscall.Overlapped{HEvent: event}, nil
  }
docs: // newOverlapped creates a structure used to track asynchronous
  // I/O requests that have been issued.