code: func (e *ProtobufReplyEncoder) Encode(r *Reply) error {
  	replyBytes, err := r.Marshal()
  	if err != nil {
  		return err
  	}
  	bs := make([]byte, 8)
  	n := binary.PutUvarint(bs, uint64(len(replyBytes)))
  	e.buffer.Write(bs[:n])
  	e.buffer.Write(replyBytes)
  	return nil
  }
docs: // Encode ...