using System;

using System.Threading;

using System.Threading.Tasks;

​

public class Program

{

    public static async Task Main()

    {

        Print("Before Task.Run");

        Task task = Task.Run(() => DoWorkAsync());

        Print("After Task.Run");

        Thread.Sleep(1000);

        Print("Before Task.WhenAll");

        Task whenAllTask = Task.WhenAll(task);

        Thread.Sleep(1000);

        Print("Before await whenAllTask");

        await whenAllTask;

        Print("After await whenAllTask");

​

        static async Task DoWorkAsync()

        {

            Print("--Starting work");

            await Task.Delay(3000);

            Print("--Finishing work");

        }

​

        static void Print(object value)

        {

            Console.WriteLine($@"{DateTime.Now:HH:mm:ss.fff} [{Thread.CurrentThread

                .ManagedThreadId}] > {value}");

        }

    }

}

​