C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.SessionState;
using System.Threading;
using System.Threading.Tasks;
using System.Net;

using Telegram.Bot;
using Telegram.Bot.Args;
using Telegram.Bot.Types;
using Telegram.Bot.Types.Enums;
using Telegram.Bot.Types.ReplyMarkups;
using System.IO;



namespace EC
{

public class Global : System.Web.HttpApplication
    {

        Telegram.Bot.TelegramBotClient Bot = new TelegramBotClient("xxxxxx");

        protected void Application_Start()
        {
            ServicePointManager.Expect100Continue = true;
            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

            Bot.OnMessage += Bot_OnMessage;
            Bot.OnUpdate += Bot_OnUpdate;
            Bot.StartReceiving();

        }

        private void Bot_OnMessage(object sender, MessageEventArgs messageEventArgs)
        {
            var message = messageEventArgs.Message;

            if (message == null || message.Type != MessageType.Text) return;

            if (message.Text.Contains("/start"))
            {
                string Str = "Start Received";

                Bot.SendTextMessageAsync(message.Chat.Id, Str);

            }
            else if (message.Text.Contains("/Stop"))
            {
                string Str = "Stop Received";
                Bot.SendTextMessageAsync(message.Chat.Id, Str);
            }
        }
 }