private void RemoveUser(MixedRealityToolkit.Sharing.User XUser)
        {
            int id = XUser.GetID();

            App.Current.Dispatcher.BeginInvoke(new Action <SessionData>((sender) =>
            {
                User existingUser = this.sessionUsers.FirstOrDefault(x => x.Id == id);
                if (existingUser != null)
                {
                    this.sessionUsers.Remove(existingUser);
                }
            }), new object[] { this });
        }
        private void AddUser(MixedRealityToolkit.Sharing.User XUser)
        {
            string userName  = XUser.GetName().GetString();
            int    id        = XUser.GetID();
            bool   muteState = XUser.GetMuteState();

            App.Current.Dispatcher.BeginInvoke(new Action <SessionData>((sender) =>
            {
                User existingUser = this.sessionUsers.FirstOrDefault(x => x.Id == id);
                if (existingUser == null)
                {
                    this.sessionUsers.Add(new User(XUser, userName, id, muteState));
                }
            }), new object[] { this });
        }