Switch to new event system (#9)

* `SignalEvents` and `synchronized` mode for `EventsListenable`

* cascade syntax

* clean up

* `RoomEvents`

* `ParticipantEvents`

* all events implemented

* make it compile with M1 macs

* dispose logic

* cleaner connect logic

* ask to publish

* fix initial EngineTrackAddedEvent glitch

* fix unpublishTrack bug

* clean up

* better events docs

* organize event types

* clean up

* cleaner wait logic

* wait for event instead of using Completer

* notifyListeners

lib/src/types.dart

@@ -1,18 +1,37 @@
-//
-// LiveKit
-//
-
 import 'package:flutter/material.dart';
 
 import 'extensions.dart';
 
 typedef CancelListenFunc = Function();
 
+enum ProtocolVersion {
+  protocol2,
+  protocol3,
+}
+
+enum ConnectionState {
+  disconnected,
+  connected,
+  reconnecting,
+}
+
 enum Reliability {
   reliable,
   lossy,
 }
 
+enum CloseReason {
+  network,
+  // ...
+}
+
+enum TrackSubscribeFailReason {
+  invalidServerResponse,
+  notTrackMetadataFound,
+  unsupportedTrackType,
+  // ...
+}
+
 enum RTCIceTransportPolicy {
   all,
   relay,
@@ -89,3 +108,14 @@ class RTCIceServer {
         if (credential?.isNotEmpty ?? false) 'credential': credential,
       };
 }
+
+@immutable
+class TrackDimension {
+  final int width;
+  final int height;
+
+  const TrackDimension(
+    this.width,
+    this.height,
+  );
+}