// Attaches Cache-Busting functionality to an endpoint
//   - Sets ETag header to provided hash
//   - Replies with 304 Not Modified, if If-None-Match header matches hash
//
// hash should be the value of calculateETag on object. If hash is empty, then
// the object is simply serialized without E-Tag functionality
func ServeHTTPWithETag(
	object runtime.Object,
	hash string,
	targetGV schema.GroupVersion,

	cacheLoad := rdm.cache.Load()
	if cacheLoad != nil {
		return cacheLoad
	}
	response := apidiscoveryv2.APIGroupDiscoveryList{
		Items: rdm.calculateAPIGroupsLocked(),
	}
	etag, err := calculateETag(response)
	if err != nil {
		klog.Errorf("failed to calculate etag for discovery document: %s", etag)
		etag = ""
	}
	cached := &cachedGroupList{
		cachedResponse:     response,
		cachedResponseETag: etag,