code: func (b *LabelManagerConnectBody) Serialize(version uint8) ([]byte, error) {
  	buf := make([]byte, 3)
  	buf[0] = uint8(b.RedistDefault)
  	binary.BigEndian.PutUint16(buf[1:3], b.Instance)
  	return buf, nil
  }
docs: // Reference: lm_label_manager_connect in lib/zclient.c of FRR