private static final class RecordingSubscriberExceptionHandler
      implements SubscriberExceptionHandler {
    private SubscriberExceptionContext context;
    private Throwable exception;

    @Override
    public void handleException(Throwable exception, SubscriberExceptionContext context) {
      this.exception = exception;
      this.context = context;
    }
  }

  private static final class RecordingSubscriberExceptionHandler
      implements SubscriberExceptionHandler {
    private SubscriberExceptionContext context;
    private Throwable exception;

    @Override
    public void handleException(Throwable exception, SubscriberExceptionContext context) {
      this.exception = exception;
      this.context = context;
    }
  }