修复开启转协议后，无人观看掐流延时不定期的bug

src/Common/MediaSource.h

@@ -53,9 +53,9 @@ public:
     virtual bool setupRecord(MediaSource &sender, Recorder::type type, bool start, const string &custom_path) { return false; };
     // 获取录制状态
     virtual bool isRecording(MediaSource &sender, Recorder::type type) { return false; };
-private:
     // 通知无人观看
-    void onNoneReader(MediaSource &sender);
+    virtual void onNoneReader(MediaSource &sender);
+
 private:
     Timer::Ptr _async_close_timer;
 };