gistfile1.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace ClientServer
{
    class Program
    {
        private static TcpListener listener;

        static void Main(string[] args)
        {
            ThreadPool.SetMinThreads(20, 20);
            StartListener();

            var watch = Stopwatch.StartNew();
            for (var i = 0; i < 20; i++)
            {
                ExecuteClient();
            }

            Console.WriteLine("20 clients in: " + watch.ElapsedMilliseconds + "ms");
            Console.WriteLine("Hit Enter to quit");
            Console.ReadLine();
            listener.Stop();
        }

        private static void StartListener()
        {
            listener = new TcpListener(new IPEndPoint(IPAddress.Any, 8012));
            listener.Start();
            AcceptLoop();
        }

        private static void AcceptLoop()
        {
            listener.BeginAcceptTcpClient(ar =>
            {
                var tcpClient = listener.EndAcceptTcpClient(ar);

                ThreadPool.QueueUserWorkItem(delegate
                {
                    HandleIncomingClientRequestOnThread(tcpClient);
                });

                AcceptLoop();
            }, null);
        }

        private static void HandleIncomingClientRequestOnThread(TcpClient tcpClient)
        {
            var stream = tcpClient.GetStream();
            ReadSomeData(stream);
            WriteSomeData(stream);
            tcpClient.Close();
        }

        private static void ExecuteClient()
        {
            using (var client = new TcpClient())
            {
                client.Connect("localhost", 8012);

                using (var stream = client.GetStream())
                {
                    WriteSomeData(stream);
                    ReadSomeData(stream);
                }
            }
        }

        static void WriteSomeData(NetworkStream stream)
        {
            var buffer = new byte[50];
            new Random().NextBytes(buffer);
            stream.Write(buffer, 0, 50);
        }

        static void ReadSomeData(NetworkStream stream)
        {
            var buffer = new byte[50];
            var read = stream.Read(buffer, 0, buffer.Length);
            Debug.Assert(read == 50);
        }
    }
}