如何发送“hello＆rdquo;服务器并回复“嗨”？

client

var cli = new TcpClient();

cli.Connect("127.0.0.1", 6800);

string data = String.Empty;

using (var ns = cli.GetStream())
{
    using (var sw = new StreamWriter(ns))
    {
        sw.Write("Hello");
        sw.Flush();

        //using (var sr = new StreamReader(ns))
        //{
        //    data = sr.ReadToEnd();
        //}
    }
}

cli.Close();

server

tcpListener = new TcpListener(IPAddress.Any, port);
tcpListener.Start();

while (run)
{
    var client = tcpListener.AcceptTcpClient();

    string data = String.Empty;

    using (var ns = client.GetStream())
    {
        using (var sr = new StreamReader(ns))
        {
            data = sr.ReadToEnd();

            //using (var sw = new StreamWriter(ns))
            //{
            //    sw.WriteLine("Hi");
            //    sw.Flush();
            //}
        }
    }
    client.Close();
}