code: func (c *RPCClient) Respond(id uint64, buf []byte) error {
  	header := requestHeader{
  		Command: respondCommand,
  		Seq:     c.getSeq(),
  	}
  	req := respondRequest{
  		ID:      id,
  		Payload: buf,
  	}
  	return c.genericRPC(&header, &req, nil)
  }
docs: // Respond allows a client to respond to a query event. The ID is the
  // ID of the Query to respond to, and the given payload is the response.