public void Dispose()
        {
            _count--;

            if (_count <= 0)
            {
                _session = null;
            }
        }
        public static ChangeNotificationSession Start()
        {
            if (_session != null)
            {
                _count++;
                return _session;
            }

            _session = new ChangeNotificationSession();
            _count = 1;

            return _session;
        }