Fix signal resume events (#1027)

Emit RoomReconnectedEvent after signal resume. Fix _sendSyncState()
timing to run after WS reconnects instead of before. Add
RoomResumingEvent separate from RoomReconnectingEvent with shared
ReconnectingEvent base mixin.

Author: hiroshihorie

.changes/fix-signal-resume-events

@@ -0,0 +1 @@
+patch type="fixed" "Fix missing RoomReconnectedEvent and incorrect SyncState timing during signal-only reconnection"

lib/src/core/room.dart

@@ -499,6 +499,7 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
     ..on<EngineResumedEvent>((event) async {
       // re-send tracks permissions
       localParticipant?.sendTrackSubscriptionPermissions();
+      events.emit(const RoomReconnectedEvent());
       notifyListeners();
     })
     ..on<EngineFullRestartingEvent>((event) async {
@@ -536,9 +537,12 @@ class Room extends DisposableChangeNotifier with EventsEmittable<RoomEvent> {
       notifyListeners();
     })
     ..on<EngineResumingEvent>((event) async {
-      await _sendSyncState();
+      events.emit(const RoomResumingEvent());
       notifyListeners();
     })
+    ..on<SignalReconnectedEvent>((event) async {
+      await _sendSyncState();
+    })
     ..on<EngineAttemptReconnectEvent>((event) async {
       events.emit(RoomAttemptReconnectEvent(
         attempt: event.attempt,

lib/src/events.dart

@@ -66,16 +66,30 @@ class RoomConnectedEvent with RoomEvent {
   String toString() => '${runtimeType}(room: ${room}, metadata: ${metadata})';
 }
 
+/// Base type for reconnecting events. Listen for this type to handle
+/// both full reconnects and signal-only reconnects.
+mixin ReconnectingEvent implements RoomEvent {}
+
 /// When the connection to the server has been interrupted and it's attempting
-/// to reconnect.
+/// a full reconnect (peer connections are reset, media is interrupted).
 /// Emitted by [Room].
-class RoomReconnectingEvent with RoomEvent {
+class RoomReconnectingEvent with RoomEvent, ReconnectingEvent {
   const RoomReconnectingEvent();
 
   @override
   String toString() => '${runtimeType}()';
 }
 
+/// When the signal connection has been interrupted and it's attempting
+/// to resume. Peer connections remain active during this type of reconnect.
+/// Emitted by [Room].
+class RoomResumingEvent with RoomEvent, ReconnectingEvent {
+  const RoomResumingEvent();
+
+  @override
+  String toString() => '${runtimeType}()';
+}
+
 /// report the number of attempts to reconnect to the room.
 class RoomAttemptReconnectEvent with RoomEvent {
   final int attempt;