public TcpClientConnection(string ip, int port)
        {
            this.ip     = ip;
            this.port   = port;
            this.client = new TCPClient();

            client.ConnectCompleted    += Client_ConnectCompleted;
            client.DisconnectCompleted += Client_DisconnectCompleted;
            client.ReceiveCompleted    += Client_ReceiveCompleted;
        }
        private bool disposedValue = false;         // 要检测冗余调用

        protected virtual void Dispose(bool disposing)
        {
            if (!disposedValue)
            {
                if (disposing)
                {
                    if (client != null)
                    {
                        client.Dispose();
                    }
                }
                client = null;

                disposedValue = true;
            }
        }