code: func keyFunc(obj objectWithMeta) uint64 {
  	hash := fnv.New32a()
  	hashutil.DeepHashObject(hash, &equivalenceLabelObj{
  		namespace: obj.GetNamespace(),
  		labels:    obj.GetLabels(),
  	})
  	return uint64(hash.Sum32())
  }
docs: // keyFunc returns the key of an object, which is used to look up in the cache for it's matching object.
  // Since we match objects by namespace and Labels/Selector, so if two objects have the same namespace and labels,
  // they will have the same key.