using System;

using System.Threading;

using System.Threading.Tasks;

public class Program

{

    public static async Task Main()

    {

        await DoWithTimeout(TimeSpan.FromSeconds(5), c => Task.Delay(TimeSpan.FromSeconds(3), c));

        Console.WriteLine("First succeeded");

        await DoWithTimeout(TimeSpan.FromSeconds(5), c => Task.Delay(TimeSpan.FromSeconds(6), c));

        Console.WriteLine("Second succeeded");

    }

    public static async Task DoWithTimeout(TimeSpan timeout, Func<CancellationToken, Task> action)

    {

        CancellationTokenSource cts = new CancellationTokenSource(timeout);

        var toTask = Task.Delay(timeout, cts.Token);

        var winningTask = await Task.WhenAny(toTask, action(cts.Token));

        if( winningTask == toTask ) throw new Exception("Timeout!");

        cts.Cancel();

        await winningTask;

    }

}