util/srv/response.go
func (s *Server) RespondError(logger log.Logger, w http.ResponseWriter, err *Error) {
	s.respond(logger, w, &Response{Error: err})
}
func (s *Server) RespondError(logger log.Logger, w http.ResponseWriter, err *Error) {
	s.respond(logger, w, &Response{Error: err})
}
// RespondError sends a response with a given error.