DummySubscriber dummySubscriber = new DummySubscriber();
    setDefault(Subscriber.class, dummySubscriber.toSubscriber());
    setDefault(Method.class, DummySubscriber.subscriberMethod());
    setDefault(SubscriberExceptionContext.class, dummySubscriber.toContext());
    setDefault(Dispatcher.class, Dispatcher.immediate());
  }

  private static class DummySubscriber {