feat: support LocalTrackSubscribedEvent. (#578)

Author: cloudwebrtc

example/lib/pages/room.dart

@@ -99,6 +99,9 @@ class _RoomPageState extends State<RoomPage> {
           'Attempting to reconnect ${event.attempt}/${event.maxAttemptsRetry}, '
           '(${event.nextRetryDelaysInMs}ms delay until next attempt)');
     })
+    ..on<LocalTrackSubscribedEvent>((event) {
+      print('Local track subscribed: ${event.trackSid}');
+    })
     ..on<LocalTrackPublishedEvent>((_) => _sortParticipants())
     ..on<LocalTrackUnpublishedEvent>((_) => _sortParticipants())
     ..on<TrackSubscribedEvent>((_) => _sortParticipants())

lib/src/core/engine.dart

@@ -1015,6 +1015,11 @@ class Engine extends Disposable with EventsEmittable<EngineEvent> {
         await publisher!.addIceCandidate(event.candidate);
       }
     })
+    ..on<SignalLocalTrackSubscribedEvent>((event) async {
+      events.emit(EngineLocalTrackSubscribedEvent(
+        trackSid: event.trackSid,
+      ));
+    })
     ..on<SignalTokenUpdatedEvent>((event) {
       logger.fine('Server refreshed the token');
       token = event.token;

lib/src/core/room.dart

@@ -526,6 +526,13 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
         notifyListeners();
       }
     })
+    ..on<EngineLocalTrackSubscribedEvent>(
+      (event) => events.emit(
+        LocalTrackSubscribedEvent(
+          trackSid: event.trackSid,
+        ),
+      ),
+    )
     ..on<EngineActiveSpeakersUpdateEvent>(
         (event) => _onEngineActiveSpeakersUpdateEvent(event.speakers))
     ..on<EngineDataPacketReceivedEvent>(_onDataMessageEvent)

lib/src/core/signal_client.dart

@@ -281,6 +281,11 @@ class SignalClient extends Disposable with EventsEmittable<SignalEvent> {
           trackSid: msg.trackUnpublished.trackSid,
         ));
         break;
+      case lk_rtc.SignalResponse_Message.trackSubscribed:
+        events.emit(SignalLocalTrackSubscribedEvent(
+          trackSid: msg.trackSubscribed.trackSid,
+        ));
+        break;
       case lk_rtc.SignalResponse_Message.speakersChanged:
         events.emit(
             SignalSpeakersChangedEvent(speakers: msg.speakersChanged.speakers));

lib/src/events.dart

@@ -228,6 +228,17 @@ class LocalTrackPublishedEvent with RoomEvent, ParticipantEvent {
       '(participant: ${participant}, publication: ${publication})';
 }
 
+class LocalTrackSubscribedEvent with RoomEvent, ParticipantEvent {
+  final String trackSid;
+  const LocalTrackSubscribedEvent({
+    required this.trackSid,
+  });
+
+  @override
+  String toString() => '${runtimeType}'
+      '(trakSid: ${trackSid}})';
+}
+
 /// The local participant has unpublished one of their [Track].
 /// Emitted by [Room] and [LocalParticipant].
 class LocalTrackUnpublishedEvent with RoomEvent, ParticipantEvent {

lib/src/internal/events.dart

@@ -169,6 +169,14 @@ class EngineDisconnectedEvent with InternalEvent, EngineEvent {
   });
 }
 
+@internal
+class EngineLocalTrackSubscribedEvent with InternalEvent, EngineEvent {
+  final String trackSid;
+  const EngineLocalTrackSubscribedEvent({
+    required this.trackSid,
+  });
+}
+
 @internal
 class EngineFullRestartingEvent with InternalEvent, EngineEvent {
   const EngineFullRestartingEvent();
@@ -297,6 +305,15 @@ class SignalTrackUnpublishedEvent with SignalEvent, InternalEvent {
   });
 }
 
+@internal
+class SignalLocalTrackSubscribedEvent with SignalEvent, InternalEvent {
+  final String trackSid;
+
+  const SignalLocalTrackSubscribedEvent({
+    required this.trackSid,
+  });
+}
+
 @internal
 class SignalRoomUpdateEvent with SignalEvent, InternalEvent {
   final lk_models.Room room;