code: func (s *Stream) WriteSysExBytes(when Timestamp, msg []byte) error {
  	return convertToError(C.Pm_WriteSysEx(unsafe.Pointer(s.pmStream), C.PmTimestamp(when), (*C.uchar)(unsafe.Pointer(&msg[0]))))
  }
docs: // WriteSysExBytes writes a system exclusive MIDI message given as a []byte to the output stream.