public static long AddRangeToSetSafe(this IRedisClient redis, string setId, List <string> items, int blockSize = 500)
        {
            if (items == null || items.Count == 0)
            {
                return(0);
            }

            if (items.Count <= blockSize)
            {
                return(redis.AddRangeToSetBatch(setId, items));
            }

            return(items.ToBlocks(blockSize).Sum(block => redis.AddRangeToSetBatch(setId, block)));
        }