feat: Forward leave reason of disconnected events. (#250)

* feat: Forward leave reason of disconnected events.

* fix analyze.

* chore: print room disconnect reason when event.reason != null.

* chore: rename InternalDisconnectReason => ClientDisconnectReason.

lib/src/types/internal.dart

@@ -0,0 +1,11 @@
+import 'package:meta/meta.dart';
+
+@internal
+enum ClientDisconnectReason {
+  user,
+  peerConnectionClosed,
+  negotiationFailed,
+  signal,
+  reconnect,
+  leaveReconnect,
+}

lib/src/types/other.dart

@@ -61,12 +61,14 @@ enum StreamState {
 }
 
 enum DisconnectReason {
-  user,
-  peerConnectionClosed,
-  negotiationFailed,
-  signal,
-  reconnect,
-  leaveReconnect,
+  unknown,
+  clientInitiated,
+  duplicateIdentity,
+  serverShutdown,
+  participantRemoved,
+  roomDeleted,
+  stateMismatch,
+  joinFailure,
 }
 
 /// The reason why a track failed to publish.