void TestTimeOut()
    {
        var cts = new CancellationTokenSource();
        cts.CancelAfter(5000);

        try
        {
            var task = Task.Run(() => LongRunningOperation(cts.Token));
            task.ContinueWith(t => Console.WriteLine("Operation cancelled"), TaskContinuationOptions.OnlyOnFaulted);
            task.Wait();
        }
        catch (AggregateException e)
        {
            //Handle
        }
    }


    void LongRunningOperation(CancellationToken token)
    {
        CancellationTokenRegistration registration = token.Register(
            () =>
            {
                throw new OperationCanceledException(token);
            });

        using (registration)
        {
            // long running operation here
        }
    }

static void LongRunningOperation(CancellationToken token)
    {
        TaskCompletionSource<int> tcs1 = new TaskCompletionSource<int>();
        token.Register(() => { tcs1.TrySetCanceled(token); });
        Task.Run(() =>
        {
            // long running operation here
            Thread.Sleep(5000);
            tcs1.TrySetResult(0);
        }, token);
        tcs1.Task.Wait();
    }