/// <summary>
        /// 删除用户.
        /// </summary>
        /// <param name="data"></param>
        public void DeleteTestData(string userName)
        {
            realService.DeleteTestData(userName);


            // 判断缓存里面有没有, 如果有, 那么需要更新缓存内容.
            // 尝试从 MemCached 中获取数据.
            TestData cachedData = client.Get <TestData>(userName);

            if (cachedData != null)
            {
                client.Remove(userName);
            }
        }