/// <summary>
        /// 静态构造函数
        /// </summary>
        static MemcacheHelper()
        {
            InitServer();
            List<string> keys = Servers.Keys.ToList<string>();

           以下这段foreach 是用来做什么的。不太明白。请大虾解释下。
            foreach (var k in Servers.Keys)
            {
                SockIOPool pool = SockIOPool.GetInstance(k);
                string[] s = new string[] { Servers[k] };
                pool.SetServers(s);//设置服务器
                pool.MaxConnections = 10000;
                pool.MinConnections = 10;
                pool.SocketConnectTimeout = 1000;
                pool.SocketTimeout = 100;
                pool.Initialize();//初始化缓存线程池
            }

           //以下这段代码与上面有什么区别呢？请大虾解释下？
            //默认池
            List<string> defaultServerList=new  List<string>();
            foreach (var k in Servers.Keys) defaultServerList.Add(Servers[k]);
            SockIOPool defaultPool = SockIOPool.GetInstance("DefaultPool");
            defaultPool.SetServers(defaultServerList.ToArray());//设置服务器
            defaultPool.MaxConnections = 10000;
            defaultPool.MinConnections = 10;
            defaultPool.SocketConnectTimeout = 1000;
            defaultPool.SocketTimeout = 100;
            defaultPool.Initialize(); //初始化默认线程池
            mc = new MemcachedClient();
            mc.PoolName = "DefaultPool";

        }
        /// <summary>
        /// 初始化服务器列表，这里默认两台服务器.
        /// </summary>
        static void InitServer(){
            //这里可以写复杂灵活点，动态从配置文件获取，我这里固定了两个
           Servers.Add("Svr1", ConfigurationManager.AppSettings["Svr1"]);
           Servers.Add("Svr2", ConfigurationManager.AppSettings["Svr2"]);
        }