Better audio management (#10)

* add audio_session package

* `AudioManager` initial design

* try to integrate audio manager

* configure audio session

* `DisposeAware`

disposing if already published causes exception.

* organize

* guard flutter_webrtc calls

* websocket async fix

* use `ConnectionState` instead of `_isClosed` and `isReconnecting`

* change create audio track defaults

* update protos

* protocol 3 speaker updates

* fix exception

* emit `RoomDisconnectedEvent` only once

* fix exception

* keep track of local / remote audio tracks

* explicit types

* manage track state

* re-structure audio management

* change defaults

* unpublish all

* use experimental build

* change defaults

* configuring is optional

* call native `RTCAudioSession.setConfiguration`

* defaults adjustment

* iOS only for now

* use lib 92.4515.07

* clean up

* revert audio options for now

* remove pod source

* rename apple related audio

* `createListener` method

* organize native audio

* `SpeakingChangedEvent` only on `Participant`

* refactoring

* fix ios compile

* fix configure audio only for iOS logic

* minor fix & clean up

* change dispose logic

* format protos

* fix unpublishTrack

* `createListener` into a mixin

* simplify

* use flutter_webrtc master

* unpublish for example

* update ios icon

* android icon

* web icon

* favicon

lib/src/participant/participant.dart

@@ -1,13 +1,12 @@
 import 'package:collection/collection.dart';
-import 'package:flutter/foundation.dart';
 import 'package:meta/meta.dart';
 
-import '../classes/change_notifier.dart';
 import '../events.dart';
 import '../extensions.dart';
 import '../logger.dart';
 import '../managers/event.dart';
 import '../proto/livekit_models.pb.dart' as lk_models;
+import '../support/disposable.dart';
 import '../track/track_publication.dart';
 import 'remote_participant.dart';
 
@@ -21,7 +20,7 @@ import 'remote_participant.dart';
 
 /// Base for [RemoteParticipant] and [LocalParticipant],
 /// can not be instantiated directly.
-abstract class Participant extends LKChangeNotifier {
+abstract class Participant extends DisposableChangeNotifier with EventsEmittable<ParticipantEvent> {
   /// map of track sid => published track
   final trackPublications = <String, TrackPublication>{};
 
@@ -44,7 +43,6 @@ abstract class Participant extends LKChangeNotifier {
   bool _isSpeaking = false;
 
   // suppport for multiple event listeners
-  final events = EventsEmitter<ParticipantEvent>();
   final EventsEmitter<RoomEvent> roomEvents;
 
   /// when the participant joined the room
@@ -85,14 +83,11 @@ abstract class Participant extends LKChangeNotifier {
       logger.fine('[ParticipantEvent] $event, will notifyListeners()');
       notifyListeners();
     });
-  }
 
-  @override
-  @mustCallSuper
-  Future<void> dispose() async {
-    logger.fine('$objectId dispose()');
-    await events.dispose();
-    super.dispose();
+    onDispose(() async {
+      await events.dispose();
+      await unpublishAllTracks();
+    });
   }
 
   /// for internal use
@@ -106,7 +101,7 @@ abstract class Participant extends LKChangeNotifier {
       lastSpokeAt = DateTime.now();
     }
 
-    [events, roomEvents].emit(SpeakingChangedEvent(
+    events.emit(SpeakingChangedEvent(
       participant: this,
       speaking: speaking,
     ));
@@ -145,15 +140,17 @@ abstract class Participant extends LKChangeNotifier {
   // Must implement
   Future<void> unpublishTrack(String trackSid, {bool notify = false});
 
-  Future<void> unpublishAllTracks() async {
-    final _ = List<TrackPublication>.from(trackPublications.values);
-    for (final track in _) {
-      await unpublishTrack(track.sid);
+  Future<void> unpublishAllTracks({bool notify = false}) async {
+    final trackSids = trackPublications.keys.toSet();
+    for (final trackid in trackSids) {
+      await unpublishTrack(trackid, notify: notify);
     }
   }
 
+  //
   // Equality operators
   // Object is considered equal when sid is equal
+  //
   @override
   int get hashCode => sid.hashCode;