code: func NewMemCacheClient(delegate discovery.DiscoveryInterface) discovery.CachedDiscoveryInterface {
  	return &memCacheClient{
  		delegate:               delegate,
  		groupToServerResources: map[string]*cacheEntry{},
  	}
  }
docs: // NewMemCacheClient creates a new CachedDiscoveryInterface which caches
  // discovery information in memory and will stay up-to-date if Invalidate is
  // called with regularity.
  //
  // NOTE: The client will NOT resort to live lookups on cache misses.