/// <summary>
        /// 添加ACK 信息,供CONSUMER使用
        /// </summary>
        /// <param name="consumerUri"> </param>
        /// <param name="server"></param>
        /// <param name="ack"></param>
        public void AppendAck(string consumerUri,PhysicalServer server,ConsumerAck ack)
        {
            Guard.ArgumentNotNull(server, "server");
            Guard.ArgumentNotNull(ack, "ack");

            Output.AddOrUpdate(server.ServerDomainName,
                               s =>
                                   {
                                       var queue = new ConcurrentQueue<CBox<Tuple<string, ConsumerAck>>>();
                                       queue.Enqueue(new CBox<Tuple<string, ConsumerAck>> { Value = new Tuple<string, ConsumerAck>(consumerUri, ack) });
                                       //定时Ack
                                       _timerScheduler.Register(() =>
                                                                    {
                                                                        var tmp = server;
                                                                        RunTaskAck(tmp);
                                                                    }, s, _ackIntervalTime, false);
                                           //对于新增的SERVER 启动TASK 进行自动ACK
                                       return queue;
                                   },
                               (s, d) =>
                                   {
                                       var tmp = server;
                                       d.Enqueue(new CBox<Tuple<string, ConsumerAck>>
                                                     {Value = new Tuple<string, ConsumerAck>(consumerUri, ack)});

                                       if (d.Count >= Consts.Consumer_DefaultAckQueueBoundary) //Queue 数量大于
                                       {
                                           System.Threading.ThreadPool.QueueUserWorkItem(RunTaskAck, tmp);
                                       }
                                       return d;
                                   });
        }
 /// <summary>
 /// 发送Ack消息
 /// </summary>
 /// <param name="duration"></param>
 /// <param name="message"></param>
 private void SendAck(int duration,Message message)
 {
     var ack = new ConsumerAck
                   {
                       Duration = duration,
                       MessageID = message.ChunkSubMessage.Pub.MessageID,
                       Position = message.ChunkSubMessage.Position,
                       Timestamp = message.ChunkSubMessage.Timestamp,
                       Acks = message.Acks, 
                       Uri = PullingRequestUri
                   };
     Buffer.SendAck(message.ChunkSubMessage.ServerHostName, ack);
 }