class ClientState {

    public Set<TaskId> activeTasks() {
        return unmodifiableSet(activeTasks);
    }

    public  ClientState();
      ClientState(final int capacity);
    public  ClientState(final Set<TaskId> previousActiveTasks,
                       final Set<TaskId> previousStandbyTasks,
                       final Map<TaskId, Long> taskLagTotals,
                       final int capacity);

}