/**
  * Prepares request for loading
  *
  * @return Prepared HttpUriRequest for that VKRequest
  */
 public HttpUriRequest getPreparedRequest() {
   HttpUriRequest request = VKHttpClient.requestWithVkRequest(this);
   if (request == null) {
     VKError error = new VKError(VKError.VK_REQUEST_NOT_PREPARED);
     provideError(error);
     return null;
   }
   return request;
 }
 /** Starts loading of prepared request. You can use it instead of executeWithResultBlock */
 public void start() {
   if ((mLoadingOperation = getOperation()) == null) {
     return;
   }
   VKHttpClient.enqueueOperation(mLoadingOperation);
 }