code: func (s *Service) RegisterStatus(key string, stat Statuser) error {
  	s.statusMu.Lock()
  	defer s.statusMu.Unlock()
  
  	if _, ok := s.statuses[key]; ok {
  		return fmt.Errorf("status already registered with key %s", key)
  	}
  	s.statuses[key] = stat
  
  	return nil
  }
docs: // RegisterStatus allows other modules to register status for serving over HTTP.