@NotNull
  @RequiresBackgroundThread
  public ListSelection<? extends DiffRequestProducer> loadRequestsInBackground() {
    try {
      return loadRequestProducers();
    }
    catch (DiffRequestProducerException e) {
      return ListSelection.createSingleton(new DiffRequestProducerWrapper(new ErrorDiffRequest(e)));
    }
  }
@NotNull
  @RequiresBackgroundThread
  public ListSelection<? extends DiffRequestProducer> loadRequestsInBackground()