using System;

using System.Threading.Tasks;

public class Program

{

    public static async Task Main()

    {

        Console.WriteLine("Hello World");

        await Task.WhenAll(DoForever(), DoForever(), DoForever(), DoForever(), DoForever());

    }

    private static async Task DoForever() {

        Console.WriteLine("starting...");

        // if you remove this "useless" await, only one DoForever() will actually get started

        await Task.Delay(TimeSpan.FromMilliseconds(10));

        while (true) {}

    }

}