MultiThreadTCP/MultiThreadTCPClient/Program.cs

using System.Net.Sockets;

class Program
{
    static void Main(string[] args)
    {
        new Thread(() =>
        {
            Thread.CurrentThread.IsBackground = true;
            Connect("127.0.0.1", "Hello I'm Client 1...");
        }).Start();

        new Thread(() =>
        {
            Thread.CurrentThread.IsBackground = true;
            Connect("127.0.0.1", "Hello I'm Client 2...");
        }).Start();

        Console.ReadLine();
    }

    private static void Connect(string server, string message)
    {
        try
        {
            Int32 port = 3000;
            TcpClient client = new TcpClient(server, port);

            NetworkStream stream = client.GetStream();

            int count = 0;
            while (count++ < 3)
            {
                Byte[] data = System.Text.Encoding.ASCII.GetBytes(message);

                stream.Write(data, 0, data.Length);
                Console.WriteLine($"Sent: {message}");

                data = new Byte[256];
                string response = string.Empty;

                Int32 bytes = stream.Read(data, 0, data.Length);
                response = System.Text.Encoding.ASCII.GetString(data, 0, bytes);
                Console.WriteLine($"Received: {response}");

                Thread.Sleep(2000);
            }

            stream.Close();
            client.Close();
        }
        catch (Exception e)
        {
            Console.WriteLine($"Exception: {e}");
        }

        Console.Read();
    }
}