code: func (a *Webhook) SetExternalKubeInformerFactory(f informers.SharedInformerFactory) {
  	namespaceInformer := f.Core().V1().Namespaces()
  	a.namespaceMatcher.NamespaceLister = namespaceInformer.Lister()
  	a.hookSource = a.sourceFactory(f)
  	a.SetReadyFunc(func() bool {
  		return namespaceInformer.Informer().HasSynced() && a.hookSource.HasSynced()
  	})
  }
docs: // SetExternalKubeInformerFactory implements the WantsExternalKubeInformerFactory interface.