using System;

using System.Threading.Tasks;

​

public class Program

{

    static async Task<string> DoTaskAsync(string name, int timeout)

    {

        var start = DateTime.Now;

        Console.WriteLine("Enter {0}, {1} ms", name, timeout);

        await Task.Delay(timeout);

        Console.WriteLine("Exit {0} Duration: {1} ms", name, (DateTime.Now - start).TotalMilliseconds);

        return name;

    }

​

    static async Task DoWork1Async()

    {

        Console.WriteLine("DoWork1Async started");

​

        var t1 = DoTaskAsync("t1.1", 3000);

        var t2 = DoTaskAsync("t1.2", 2000);

        var t3 = DoTaskAsync("t1.3", 1000);

​

​

        Console.WriteLine("await t1");

        await t1;

        Console.WriteLine("await t2");

        await t2;

        Console.WriteLine("await t3");

        await t3;

​

        Console.WriteLine("DoWork1Async results: {0}", String.Join(", ", t1.Result, t2.Result, t3.Result));

    }

​

​

    static async Task Main(string[] args)

    {

        await DoWork1Async();

    }

}