class UnicastSubject extends Subject<T> {

    @Override
    public boolean hasObservers() {
        return actual.get() != null;
    }

      UnicastSubject(int capacityHint, boolean delayError);
      UnicastSubject(int capacityHint, Runnable onTerminate);
      UnicastSubject(int capacityHint, Runnable onTerminate, boolean delayError);

}