using System;

using System.Collections.Generic;

using System.Diagnostics;

using System.Threading;

using System.Threading.Tasks;

​

namespace AsyncThreadDemo

{

    class Program

    {

        static async Task Main(string[] args)

        {

            int number = Process.GetCurrentProcess().Threads.Count;

            Console.WriteLine($"Init thread count: {number}");

            Console.WriteLine($"ThreadPool.ThreadCount: {ThreadPool.ThreadCount}");

​

            await wrapped();

            //await unwrapped();

​

            number = Process.GetCurrentProcess().Threads.Count;

            Console.WriteLine($"Done thread count: {number}");

            Console.WriteLine($"ThreadPool.ThreadCount: {ThreadPool.ThreadCount}");

        }

​

        private static async Task wrapped()

        {

            Console.WriteLine($"Wrapped");

            List<Task> tasks = new List<Task>();

            tasks.AddRange(new []

            {

                Task.Run(async() => await new MyThread().RunMe()),

                Task.Run(async() => await new MyThread().RunMe()),

                Task.Run(async() => await new MyThread().RunMe()),

                Task.Run(async() => await new MyThread().RunMe()),

            });

​

            Thread.Sleep(1000);

            int number = Process.GetCurrentProcess().Threads.Count;

            Console.WriteLine($"While running thread count: {number}");

​

            await Task.WhenAll(tasks);

        }

​

        private static async Task unwrapped()

        {

            Console.WriteLine($"Unwrapped");

            List<Task> tasks = new List<Task>();

            Task<int> t1 = new MyThread().RunMe();

            Task<int> t2 = new MyThread().RunMe();

            Task<int> t3 = new MyThread().RunMe();

            Task<int> t4 = new MyThread().RunMe();

            tasks.AddRange(new[] {t1, t2, t3, t4});

​

            Thread.Sleep(1000);

            int number = Process.GetCurrentProcess().Threads.Count;

            Console.WriteLine($"While running thread count: {number}");

​

            int i1 = await t1;

            int i2 = await t2;

            int i3 = await t3;

            int i4 = await t4;

        }

    }

​

    public class MyThread

    {

        public static int _counter;

​

        public async Task<int> RunMe()

        {

            await Task.Run(() =>

            {

                for (int i = 0; i < 2; ++i)

                {

                    Thread.Sleep(1000);

                    Console.WriteLine($"T{Thread.CurrentThread.ManagedThreadId} {i}");

                }

                Console.WriteLine($"T{Thread.CurrentThread.ManagedThreadId} done");

            });

            return _counter++;

        }

    }

}