code: func NewServiceConfig(serviceInformer coreinformers.ServiceInformer, resyncPeriod time.Duration) *ServiceConfig {
  	result := &ServiceConfig{
  		lister:       serviceInformer.Lister(),
  		listerSynced: serviceInformer.Informer().HasSynced,
  	}
  
  	serviceInformer.Informer().AddEventHandlerWithResyncPeriod(
  		cache.ResourceEventHandlerFuncs{
  			AddFunc:    result.handleAddService,
  			UpdateFunc: result.handleUpdateService,
  			DeleteFunc: result.handleDeleteService,
  		},
  		resyncPeriod,
  	)
  
  	return result
  }
docs: // NewServiceConfig creates a new ServiceConfig.