message: Publicly expose Subscription::result_set_object()
diff: @@ -100,11 +100,11 @@ public:
  SubscriptionNotificationToken add_notification_callback(std::function<void()> callback);
  + util::Optional<Object> result_set_object() const;
  +
  private:
  Subscription(std::string name, std::string object_type, std::shared_ptr<Realm>);
  - util::Optional<Object> result_set_object() const;
  -
  void error_occurred(std::exception_ptr);
  void run_callback(SubscriptionCallbackWrapper& callback_wrapper);
  