Adding start/stop watching event

packages/stream_chat/lib/src/client/channel.dart

@@ -1754,6 +1754,26 @@ class ChannelClientState {
     ));
   }
 
+  void _listenUserStartWatching() {
+    _subscriptions.add(
+      _channel.on(EventType.userWatchingStart).listen((event) {
+        if (event.user != null) {
+          _incrementWatcher(event.user!);
+        }
+      }),
+    );
+  }
+
+  void _listenUserStopWatching() {
+    _subscriptions.add(
+      _channel.on(EventType.userWatchingStop).listen((event) {
+        if (event.user != null) {
+          channelState.watchers?.remove(event.user);
+        }
+      }),
+    );
+  }
+
   void _listenMemberUnbanned() {
     _subscriptions.add(_channel
         .on(EventType.userUnbanned)
@@ -1770,6 +1790,19 @@ class ChannelClientState {
     ));
   }
 
+  void _incrementWatcher(User user) {
+    List<User> newWatchers;
+
+    if (channelState.watchers == null) {
+      channelState.watchers!.add(user);
+      newWatchers = channelState.watchers!;
+    } else {
+      newWatchers = [user];
+    }
+
+    channelState.copyWith(watchers: newWatchers);
+  }
+
   void _updateMember(Member member) {
     final currentMembers = [...members];
     final memberIndex = currentMembers.indexWhere(

packages/stream_chat/lib/src/event_type.dart

@@ -36,6 +36,12 @@ class EventType {
   /// Event sent when updating a message
   static const String messageUpdated = 'message.updated';
 
+  /// Event sent when a user starts watching a channel
+  static const String userWatchingStart = 'user.watching.start';
+
+  /// Event sent when a user stops watching a channel
+  static const String userWatchingStop = 'user.watching.stop';
+
   /// Event sent when reading a message
   static const String messageRead = 'message.read';