using System;

using System.Threading;

using System.Threading.Tasks;

using System.Collections.Generic;

using System.Diagnostics;

​

namespace Test

{

    public class Program

    {

        public static void Main(string[] args)

        {

            var tasks = new List<Task>();

            var sw = new Stopwatch();

            sw.Start();

            var maxThreads = 4;

            ThreadPool.SetMaxThreads (maxThreads, maxThreads);

            for (int i = 0; i < maxThreads; i++) {

                var taskId = i;

                Console.WriteLine($"Task #{taskId} run");

                var task = Task.Run(() => {

                    Console.WriteLine($"Task #{taskId} started {sw.ElapsedMilliseconds}");

                    Thread.Sleep(5000);

                    Console.WriteLine($"Task #{taskId} finished {sw.ElapsedMilliseconds}");

                });

                tasks.Add(task);

            }

            for (int i = 0; i < maxThreads; i++) {

                var taskId = i;

                Console.WriteLine($"Task Set 2 #{taskId} run");

                var task = Task.Run(() => {

                    Console.WriteLine($"Task Set 2 #{taskId} started {sw.ElapsedMilliseconds}");

                    Thread.Sleep(500);

                    Console.WriteLine($"Task Set 2 #{taskId} finished {sw.ElapsedMilliseconds}");

                });

                tasks.Add(task);

            }

            Console.WriteLine($"waiting");

            Task.WaitAll(tasks.ToArray());

        }

    }

}