code: func (s *HTTPServer) KeyringUse(resp http.ResponseWriter, req *http.Request, args *keyringArgs) (interface{}, error) {
  	responses, err := s.agent.UseKey(args.Key, args.Token, args.RelayFactor)
  	if err != nil {
  		return nil, err
  	}
  
  	return nil, keyringErrorsOrNil(responses.Responses)
  }
docs: // KeyringUse is used to change the primary gossip encryption key