@Override
  public void onLiveInstanceChange(List<LiveInstance> liveInstances, NotificationContext changeContext) {
    for (LiveInstanceChangeListener registeredLiveInstanceChangeListener : registeredLiveInstanceChangeListeners) {
      registeredLiveInstanceChangeListener.onLiveInstanceChange(liveInstances, changeContext);
    }
  }
Constructor for {@link HelixVcrClusterSpectator}.
@param cloudConfig Cluster config of vcr.
@param clusterMapConfig Cluster Map config.
ambry-cloud/src/main/java/com/github/ambry/cloud/HelixVcrClusterSpectator.java