code: protected RequestProcessor createRequestProcessor(CacheManager cacheManager, RequestProgressManager requestProgressManager, RequestRunner requestRunner) {
          return new RequestProcessor(cacheManager, requestProgressManager, requestRunner);
      }
docs: Factory method to create an entity responsible for processing requests
  send to the SpiceService. The default implementation of this method will
  return a {@link RequestProcessor}. Override this method if you want to
  inject a custom request processor. This feature has been implemented
  following a request from Christopher Jenkins.
  @param cacheManager
  the cache manager used by this service.
  @param requestProgressManager
  will notify of requests progress.
  @param requestRunner
  executes requests.
  @return a {@link RequestProcessor} that will be used to process requests.