code: func readKeyString(r *bufio.Reader) (key string, msg string, err error) {
  	key, err = readString1(r)
  	if err != nil {
  		return
  	}
  	msg, err = readString2(r)
  	if err != nil {
  		return
  	}
  	return
  }
docs: //KEY_VALUE has been read already.