修复mk_media_source_get_track接口崩溃问题:#2552

api/include/mk_events_objects.h

@@ -98,7 +98,7 @@ API_EXPORT int API_CALL mk_media_source_get_reader_count(const mk_media_source c
 API_EXPORT int API_CALL mk_media_source_get_total_reader_count(const mk_media_source ctx);
 // get track count from MediaSource
 API_EXPORT int API_CALL mk_media_source_get_track_count(const mk_media_source ctx);
-// get track by index from MediaSource
+// copy track reference by index from MediaSource, please use mk_track_unref to release it
 API_EXPORT mk_track API_CALL mk_media_source_get_track(const mk_media_source ctx, int index);
 /**
  * 直播源在ZLMediaKit中被称作为MediaSource，

api/source/mk_events_objects.cpp

@@ -211,7 +211,7 @@ API_EXPORT mk_track API_CALL mk_media_source_get_track(const mk_media_source ctx
     if (index < 0 && index >= tracks.size()) {
         return nullptr;
     }
-    return reinterpret_cast<mk_track>(& (tracks[index]));
+    return (mk_track) new Track::Ptr(std::move(tracks[index]));
 }
 
 API_EXPORT int API_CALL mk_media_source_close(const mk_media_source ctx,int force){