code: public void notifyObserversOfRequestNotFound(CachedSpiceRequest<?> request) {
          RequestProcessingContext requestProcessingContext = new RequestProcessingContext();
          requestProcessingContext.setExecutionThread(Thread.currentThread());
          post(new RequestNotFoundNotifier(request, spiceServiceListenerList, requestProcessingContext));
      }
docs: Inform the observers of a request. The observers can optionally observe
  the new request if required.
  @param request the request that couldn't be aggregated to another request.