code: func (s *serviceConfigWatch) Start() error {
  	s.ctx, s.cancelFunc = context.WithCancel(context.Background())
  	if err := s.ensureConfigWatch(); err != nil {
  		return err
  	}
  	go s.runWatch()
  
  	return nil
  }
docs: // Start starts the config watch and a goroutine to handle updates over
  // the updateCh. This is not safe to call more than once.