Client ssl.cs

using System;
using System.IO;
using System.Net.Security;
using System.Net.Sockets;
using System.Text;

namespace SslBug
{
    class Program
    {
        static void Main(string[] args)
        {
            Test();
            Console.ReadKey();
        }

        static async void Test()
        {
            string serverAddress = "localhost";
            int port = 8080;

            Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            socket.ReceiveTimeout = 10000;
            socket.NoDelay = true;
            socket.SendBufferSize = 8000;
            socket.ReceiveBufferSize = 8000;
            socket.Connect(serverAddress, port);

            var tcpStream = new NetworkStream(socket, true);
            var sslStream = new SslStream(tcpStream, true, (s, cert, chain, policy) => true, null);
            sslStream.AuthenticateAsClientAsync(serverAddress).GetAwaiter().GetResult();
            SendMessage('c', sslStream);
            var msg1 = ReadMessage(sslStream);
            Console.WriteLine($"Received SSL message: {msg1.Substring(0, 10)}...");

            sslStream.Dispose();
            sslStream = null;
            
            socket.Poll(0, SelectMode.SelectError);

            SendMessage('c', tcpStream);
            var msg2 = ReadMessage(tcpStream);
            Console.WriteLine($"Received PLAIN message: {msg2.Substring(0, 10)}...");
            Console.WriteLine("Done.");
        }

        static void SendMessage(char c, Stream stream)
        {
            var msg = new string(c, 8000) + "<EOF>";
            var bytes = Encoding.UTF8.GetBytes(msg);
            stream.Write(bytes, 0, bytes.Length);
            //stream.Flush();
        }

        static string ReadMessage(Stream stream)
        {
            // Read the  message sent by the client.
            // The client signals the end of the message using the
            // "<EOF>" marker.
            byte[] buffer = new byte[2048];
            StringBuilder messageData = new StringBuilder();
            int bytes = -1;
            do
            {
                // Read the client's test message.
                bytes = stream.Read(buffer, 0, buffer.Length);

                // Use Decoder class to convert from bytes to UTF8
                // in case a character spans two buffers.
                Decoder decoder = Encoding.UTF8.GetDecoder();
                char[] chars = new char[decoder.GetCharCount(buffer, 0, bytes)];
                decoder.GetChars(buffer, 0, bytes, chars, 0);
                messageData.Append(chars);
                // Check for EOF or an empty message.
                if (messageData.ToString().IndexOf("<EOF>") != -1)
                {
                    break;
                }
            } while (bytes != 0);

            return messageData.ToString();
        }
    }
}