code: public static BaasResult<JsonObject> fetchDataSync(String id){
          if (id == null) throw new IllegalArgumentException("asset id cannot be null");
          BaasBox box = BaasBox.getDefaultChecked();
          AssetDataRequest req = new AssetDataRequest(box,id, RequestOptions.DEFAULT,null);
          return box.submitSync(req);
      }
docs: Synchronously retrieves named assets data,
  If the named asset is a document, the document is retrieved
  otherwise attached data to the file are returned.
  
  @param id the name of the asset
  @return a baas result wrapping the response.