TBConsole/TBConsole/WebServer.cs

using System;
using System.IO;
using System.Net;

namespace TBConsole
{
    public class WebServer
    {
        private bool _running;
        private readonly HttpListener _listener = new HttpListener();
        private Func<string, string> _receiver;
        public WebServer(Func<string, string> receiver) => _receiver = receiver;
        
        public void Start()
        {
            _running = true;
            KeepListening();
        }

        public void Stop()
        {
            _running = false;
            _listener.Stop();
        }
        
        private async void KeepListening()
        {
            _listener.Prefixes.Add("http://localhost:8019/");
            _listener.Start();
            while (_running)
            {
                var context = await _listener.GetContextAsync();
                string resp = _receiver(await new StreamReader(context.Request.InputStream).ReadToEndAsync());
                var sw = new StreamWriter(context.Response.OutputStream);
                await sw.WriteLineAsync(resp);
                sw.Close();
            }
        }
    }
}