code: protected void callback(String name, Bundle resultData) {
      if (resultData == null) resultData = new Bundle();
      resultData.putString(Groundy.KEY_CALLBACK_NAME, name);
      resultData.putSerializable(Groundy.TASK_IMPLEMENTATION, getClass());
      send(OnCallback.class, resultData);
    }
docs: Sends this data to the callback methods annotated with the specified name.
  
  @param name the name of the callback to invoke
  @param resultData optional arguments to send