public void addListener(@NotNull DiffRequestProcessorListener listener, @Nullable Disposable disposable) {
    if (disposable != null) {
      myEventDispatcher.addListener(listener, disposable);
    }
    else {
      myEventDispatcher.addListener(listener);
    }
  }
public void addListener(@NotNull DiffRequestProcessorListener listener, @Nullable Disposable disposable)