public static void ForEachWithIndex<TKey>(this IEnumerable<TKey> list, Action<TKey, int> compute)
    {
        if (list == null)
            return;
        var rlist = list.ToList();
        int count = rlist.Count;
        for (int i = 0; i < count; i++)
        {
            compute(rlist[i], i);
        }
    }