fix: close async lifecycle races

lib/services/discord_rpc_service.dart

@@ -53,6 +53,7 @@ class DiscordRPCService {
   Duration? _mediaDuration;
   Duration? _currentPosition;
   double _playbackSpeed = 1.0;
+  int _playbackRevision = 0;
   Timer? _reconnectTimer;
   DateTime? _lastPresenceUpdate;
   StreamSubscription<void>? _readySubscription;
@@ -106,6 +107,7 @@ class DiscordRPCService {
   /// thumbnail upload uses the neutral [MediaServerClient.thumbnailUrl] /
   /// [MediaServerClient.streamHeaders] surface.
   Future<void> startPlayback(MediaItem metadata, MediaServerClient client) async {
+    final revision = ++_playbackRevision;
     _currentMetadata = metadata;
     _currentClient = client;
     _playbackStartTime = DateTime.now();
@@ -116,7 +118,7 @@ class DiscordRPCService {
 
     if (_isEnabled && _isConnected) {
       // Upload thumbnail in background, don't block playback
-      unawaited(_uploadThumbnailAndUpdatePresence());
+      unawaited(_uploadThumbnailAndUpdatePresence(revision, metadata, client));
     }
   }
 
@@ -172,6 +174,7 @@ class DiscordRPCService {
   }
 
   Future<void> stopPlayback() async {
+    _playbackRevision++;
     _currentMetadata = null;
     _currentClient = null;
     _playbackStartTime = null;
@@ -211,8 +214,10 @@ class DiscordRPCService {
         await Future.delayed(const Duration(milliseconds: 200));
 
         // Update presence if we have active playback
-        if (_currentMetadata != null) {
-          await _uploadThumbnailAndUpdatePresence();
+        final metadata = _currentMetadata;
+        final client = _currentClient;
+        if (metadata != null && client != null) {
+          await _uploadThumbnailAndUpdatePresence(_playbackRevision, metadata, client);
         }
       });
 
@@ -276,11 +281,12 @@ class DiscordRPCService {
     });
   }
 
-  Future<void> _uploadThumbnailAndUpdatePresence() async {
-    // Try to upload thumbnail, but don't block on failure
-    if (_cachedThumbnailUrl == null && _currentMetadata != null && _currentClient != null) {
-      _cachedThumbnailUrl = await _uploadThumbnail(_currentMetadata!, _currentClient!);
+  Future<void> _uploadThumbnailAndUpdatePresence(int revision, MediaItem metadata, MediaServerClient client) async {
+    final thumbnailUrl = await _uploadThumbnail(metadata, client);
+    if (revision != _playbackRevision || !identical(_currentMetadata, metadata) || !identical(_currentClient, client)) {
+      return;
     }
+    _cachedThumbnailUrl = thumbnailUrl;
     await _updatePresence();
   }
 

lib/watch_together/services/watch_together_peer_service.dart

@@ -300,7 +300,6 @@ class WatchTogetherPeerService with KeepaliveMixin {
       try {
         final channel = await _connectToRelay();
         _channel = channel;
-        _reconnectAttempts = 0;
 
         final completer = Completer<void>();
         _listenToChannel(channel, setupCompleter: completer);
@@ -328,8 +327,13 @@ class WatchTogetherPeerService with KeepaliveMixin {
           }
         }
 
+        _reconnectAttempts = 0;
         appLogger.d('WatchTogether: Reconnected successfully');
-        onReconnected?.call();
+        try {
+          onReconnected?.call();
+        } catch (e) {
+          appLogger.e('WatchTogether: Reconnect callback failed', error: e);
+        }
       } catch (e) {
         appLogger.e('WatchTogether: Reconnect failed', error: e);
         _handleWebSocketClosed();

lib/widgets/video_controls/widgets/performance_overlay/performance_stats_service.dart

@@ -78,14 +78,15 @@ class PerformanceStatsService {
     _fpsTrackingActive = true;
     if (!_fpsCallbackRegistered) {
       _fpsCallbackRegistered = true;
-      SchedulerBinding.instance.addPersistentFrameCallback(_onFrame);
+      SchedulerBinding.instance.addTimingsCallback(_onFrameTimings);
     }
   }
 
-  /// Called every frame to count FPS.
-  void _onFrame(Duration timestamp) {
+  /// Called with completed frame timings to count FPS without retaining an
+  /// app-lifetime persistent callback.
+  void _onFrameTimings(List<FrameTiming> timings) {
     if (!_fpsTrackingActive) return;
-    _frameCount++;
+    _frameCount += timings.length;
     final now = DateTime.now();
     final elapsed = now.difference(_lastFpsUpdate);
     if (elapsed.inMilliseconds >= 1000) {
@@ -101,6 +102,10 @@ class PerformanceStatsService {
     _pollingTimer = null;
     _fpsTrackingActive = false;
     _currentUiFps = null;
+    if (_fpsCallbackRegistered) {
+      SchedulerBinding.instance.removeTimingsCallback(_onFrameTimings);
+      _fpsCallbackRegistered = false;
+    }
   }
 
   /// Fetch all performance stats from the player.