using System;

using System.Threading;

using System.Threading.Tasks;

​

public class AwaitOperator

{

    private static DateTime startPoint;

    private static void trace(object msg)

    {

        TimeSpan timeShift = DateTime.UtcNow - startPoint;

        Console.WriteLine(String.Format("{0:D2}.{1:D3}: {2}", timeShift.Seconds, timeShift.Milliseconds, msg));

    }

    public static async Task Main()

    {

        startPoint = DateTime.UtcNow;

        trace("Async pool launched");

        Task<int> proc1 = Process1();

        Task<int> proc2 = Process2();

        Task<int> proc3 = Process3();

​

        int v1 = await proc1;

        trace(v1);

        int v2 = await proc2;

        trace(v2);

        int v3 = await proc3;

        trace(v3);

        trace("Async pool complete");

    }

​

    private static async Task<int> Process1()

    {

        trace("Process #1 run");

        await Task.Run( () => Thread.Sleep(1500) );

        trace("Process #1 exit");

        return 10;

    }

​

    private static async Task<int> Process2()

    {

        trace("Process #2 run");

        await Task.Run( () => Thread.Sleep(1000) );

        trace("Process #2 exit");

        return 20;

    }

​

    private static async Task<int> Process3()

    {

        trace("Process #3 run");

        await Task.Run( () => Thread.Sleep(500) );

        trace("Process #3 exit");

        return 30;

    }

}