using System;

using System.Threading;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        CancellationTokenSource source = new CancellationTokenSource();

        CancellationToken token = source.Token;

        var task = Task.Run(() => Test(), token);

        Console.WriteLine("Hello World");

        Thread.Sleep(1000);

        Console.WriteLine("Cancelling");

        source.Cancel();

        Task.WaitAll(task);

        Console.WriteLine("Bye World");

    }

    public static void Test(){

        Console.WriteLine("I am started");

        Thread.Sleep(8000);

    }

}