@Override
  public VcrClusterParticipant getVcrClusterParticipant() throws Exception {
    return null;
  }
Constructor for {@link MockVcrClusterAgentsFactory} object.
@param cloudDataNodes list of cloud {@link MockDataNodeId}s in instance config of {@link MockVcrClusterSpectator}.
ambry-test-utils/src/main/java/com/github/ambry/clustermap/MockVcrClusterAgentsFactory.java