Reactive Stream API.java

public interface Publisher<T> {
    void subscribe(Subscriber<? super T> s);
}

public interface Subscriber<T> {
    void onSubscribe(Subscription s);
    void onNext(T t);
    void onError(Throwable t);
    void onComplete();
}

public interface Processor<T, R> extends Subscriber<T>, Publisher<R> {
}

public interface Subscription {
    void request(long n);
    void cancel();
}