code: public Postcard withObject(@Nullable String key, @Nullable Object value) {
          serializationService = ARouter.getInstance().navigation(SerializationService.class);
          mBundle.putString(key, serializationService.object2Json(value));
          return this;
      }
docs: Set object value, the value will be convert to string by 'Fastjson'
  
  @param key   a String, or null
  @param value a Object, or null
  @return current