using System;

using System.Threading.Tasks;

using System.Diagnostics;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("1");

​

        Task.Run(() => MainRun()).GetAwaiter().GetResult();

​

        Console.WriteLine("8");

    }

​

    private static async Task MainRun()

    {

        Console.WriteLine("2");

​

        Func<Task> taskDelay = () => TaskDelay(100);

​

        Console.WriteLine("3");

        await taskDelay(); // só aqui TaskDelay será executado

​

        Console.WriteLine("7");

    }

​

    private static async Task TaskDelay(int millisecondsTimeout)

    {

        var sw = Stopwatch.StartNew();

​

        Console.WriteLine($"4");

        await Task.Delay(millisecondsTimeout);

        Console.WriteLine($"5");

        sw.Stop();

​

        Console.WriteLine($"6 TaskDelay.Task delay completed in {sw.ElapsedMilliseconds}ms");

    }

}

​