using System;

using System.Threading.Tasks;

using System.Threading;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    static int count = 0;

    public static async void Main()

    {

        var  arr =  new List<int> ( new int[1000] );

        var list = arr.Select(x=> Task.Run(()=> Do())).ToList();

        await Task.WhenAll(list);

        Console.WriteLine(count);

    }

    public static async Task Do() {

     for (int i = 0; i < 1000; i++) {

         count++;

     }

        await Task.CompletedTask;

    }

}