code: func (c *RPCClient) UpdateTags(tags map[string]string, delTags []string) error {
  	header := requestHeader{
  		Command: tagsCommand,
  		Seq:     c.getSeq(),
  	}
  	req := tagsRequest{
  		Tags:       tags,
  		DeleteTags: delTags,
  	}
  	return c.genericRPC(&header, &req, nil)
  }
docs: // UpdateTags will modify the tags on a running serf agent