Dictionary<long, long> dict = new Dictionary<long, long> ();
        List<Task> list = new List<Task>();
        for(int i = 0; i < 2000; i++)
        {
            var task = Task.Run (() =>
            {
                var newId = YitIdHelper.NextId ();
                dict.Add (newId, i);
            });
            list.Add (task);    
        }

        list.ForEach (item =>
        {
            System.Threading.Thread.Sleep (1);
            item.Wait ();
        });
        int iw = 0;