gistfile1.cs

        private void DisconnectClient(string clientId)
        {
            ChatUser user = _service.DisconnectClient(clientId);

            // There's no associated user for this client id
            if (user == null)
            {
                return;
            }

            // The user will be marked as offline if all clients leave
            if (user.Status == (int)UserStatus.Offline)
            {
                foreach (var room in user.Rooms)
                {
                    var userViewModel = new UserViewModel(user);

                    Clients[room.Name].leave(userViewModel, room.Name).Wait();

                    OnRoomCountChanged(room);
                }
            }
        }