@Override
  public void onInstanceConfigChange(List<InstanceConfig> instanceConfigs, NotificationContext context) {
    for (InstanceConfigChangeListener registeredInstanceConfigChangeListener : registeredInstanceConfigChangeListeners) {
      registeredInstanceConfigChangeListener.onInstanceConfigChange(instanceConfigs, context);
    }
  }
Constructor for {@link MockVcrClusterSpectator} object.
@param cloudDataNodeList list of cloud {@link MockDataNodeId}s in instance config of {@link MockVcrClusterSpectator}.
ambry-test-utils/src/main/java/com/github/ambry/clustermap/MockVcrClusterSpectator.java