using System;

using System.Threading;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        var fooTask =

            Task.Factory.StartNew(() =>

                {

                    Thread.Sleep(50);

                    return 42;

                });

        if (!Task.WaitAll(new []{fooTask}, TimeSpan.FromMilliseconds(300)))

        {

            throw new TaskCanceledException(fooTask);

        }

        Console.WriteLine(fooTask.Result);

    }

}