code: func (s *Service) Stop() error {
  	if s.listener != nil {
  		s.listener.Close()
  		s.listener = nil
  		log.Info("GraphQL endpoint closed", "url", fmt.Sprintf("http://%s", s.endpoint))
  	}
  	return nil
  }
docs: // Stop terminates all goroutines belonging to the service, blocking until they
  // are all terminated.