// clusters when a push for the specific cluster is needed.
type EndpointShards struct {
	// mutex protecting below map.
	sync.RWMutex

	// Shards is used to track the shards. EDS updates are grouped by shard.
	// Current implementation uses the registry name as key - in multicluster this is the
	// name of the k8s cluster, derived from the config (secret).
	Shards map[ShardKey][]*IstioEndpoint