public interface Publisher<T> {
  void subscribe(Subscriber<? super T> s);
}
public interface Subscriber<T> {
    public void onSubscribe(Subscription s);
    void onNext(T t);
    void onError(Throwable t);
    void onComplete();
}
public interface Subscription {
    public void request(long n);
    public void cancel();
}
public interface Processor<T, R> extends Subscriber<T>, Publisher<R> {
}