using System;

using System.Linq;

using System.Threading.Tasks;

public class Program

{

    public static async Task Main()

    {

        int tasksCompleted = 0;

        var list = new int[100000];

        var tasks = list.Select(i => Task.Run(() => tasksCompleted++)).ToList();

        Console.WriteLine($"{tasks.Count} tasks created");

​

        await Task.WhenAll(tasks);

        Console.WriteLine($"{tasksCompleted} tasks completed");

    }

}