using System;

using System.Threading;

using System.Threading.Tasks;

​

public class Program

{

    public static async Task Main()

    {

        Console.WriteLine("Main thread 1:" + Thread.CurrentThread.ManagedThreadId.ToString());

        //await Test1();

        await Test2();

        Console.WriteLine("Main thread 2:" + Thread.CurrentThread.ManagedThreadId.ToString());

        Console.WriteLine("main task complete!");

    }

​

    static async Task Test1()

    {

        Console.WriteLine("Second thread 1:" + Thread.CurrentThread.ManagedThreadId.ToString());

        await Task.CompletedTask;

        Console.WriteLine("Second thread 2:" + Thread.CurrentThread.ManagedThreadId.ToString());

    }

​

    static async Task Test2()

    {

        Console.WriteLine("Third thread 1:" + Thread.CurrentThread.ManagedThreadId.ToString());

        await Task.Delay(2000);

        Console.WriteLine("Third thread 2:" + Thread.CurrentThread.ManagedThreadId.ToString());

    }

}