code: boolean updateCallback(Task<?> task, Activity callback, String annotationId) {
          if (task == null || callback == null) {
              return false;
          }
  
          WeakReference<TaskRunnable<?>> reference = mTaskRunnables.get(task.getKey());
          if (reference == null) {
              return false;
          }
          TaskRunnable<?> runnable = reference.get();
          if (runnable == null || runnable.mPostingResult || runnable.mTask != task) {
              return false;
          }
  
          task.setCachedActivity(callback);
          task.setAnnotationId(annotationId);
          runnable.updateCallbackActivity(callback);
          return true;
      }
docs: /*package