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/events.dart

@@ -1,6 +1,4 @@
 import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
-import 'package:livekit_client/livekit_client.dart';
-import 'package:meta/meta.dart';
 
 import 'participant/participant.dart';
 import 'participant/remote_participant.dart';
@@ -8,6 +6,7 @@ import 'proto/livekit_models.pb.dart' as lk_models;
 import 'proto/livekit_rtc.pb.dart' as lk_rtc;
 import 'track/remote_track_publication.dart';
 import 'track/track.dart';
+import 'track/track_publication.dart';
 import 'types.dart';
 
 abstract class LiveKitEvent {}
@@ -110,14 +109,6 @@ class TrackSubscribedEvent with RoomEvent, ParticipantEvent {
   });
 }
 
-@internal
-class ParticipantInfoUpdatedEvent with ParticipantEvent {
-  final RemoteParticipant participant;
-  const ParticipantInfoUpdatedEvent({
-    required this.participant,
-  });
-}
-
 /// An error has occured during track subscription.
 /// Emitted by [Room] and [RemoteParticipant].
 class TrackSubscriptionExceptionEvent with RoomEvent, ParticipantEvent {
@@ -226,12 +217,12 @@ class EngineReconnectedEvent with EngineEvent {
   const EngineReconnectedEvent();
 }
 
-class EngineParticipantUpdateEvent with EngineEvent {
-  final List<lk_models.ParticipantInfo> participants;
-  const EngineParticipantUpdateEvent({
-    required this.participants,
-  });
-}
+// class EngineParticipantUpdateEvent with EngineEvent {
+//   final List<lk_models.ParticipantInfo> participants;
+//   const EngineParticipantUpdateEvent({
+//     required this.participants,
+//   });
+// }
 
 class EngineTrackAddedEvent with EngineEvent {
   final rtc.MediaStreamTrack track;
@@ -244,13 +235,6 @@ class EngineTrackAddedEvent with EngineEvent {
   });
 }
 
-class EngineSpeakersUpdateEvent with EngineEvent {
-  final List<lk_models.SpeakerInfo> speakers;
-  const EngineSpeakersUpdateEvent({
-    required this.speakers,
-  });
-}
-
 class EngineDataPacketReceivedEvent with EngineEvent {
   final lk_models.UserPacket packet;
   final lk_models.DataPacket_Kind kind;
@@ -363,10 +347,11 @@ class SignalTrickleEvent with SignalEvent {
   });
 }
 
-class SignalParticipantUpdateEvent with SignalEvent {
-  final List<lk_models.ParticipantInfo> updates;
+// relayed by Engine
+class SignalParticipantUpdateEvent with SignalEvent, EngineEvent {
+  final List<lk_models.ParticipantInfo> participants;
   const SignalParticipantUpdateEvent({
-    required this.updates,
+    required this.participants,
   });
 }
 
@@ -379,9 +364,19 @@ class SignalLocalTrackPublishedEvent with SignalEvent {
   });
 }
 
-class SignalActiveSpeakersChangedEvent with SignalEvent {
+// speaker update received through websocket
+// relayed by Engine
+class SignalSpeakersChangedEvent with SignalEvent, EngineEvent {
   final List<lk_models.SpeakerInfo> speakers;
-  const SignalActiveSpeakersChangedEvent({
+  const SignalSpeakersChangedEvent({
+    required this.speakers,
+  });
+}
+
+// Event received through data channel
+class EngineActiveSpeakersUpdateEvent with EngineEvent {
+  final List<lk_models.SpeakerInfo> speakers;
+  const EngineActiveSpeakersUpdateEvent({
     required this.speakers,
   });
 }