Async quiz: How many threads are used? What does it print?

async.cs

using System;
using System.Runtime.CompilerServices;
using System.Threading.Tasks;

class Program
{
    static void Main(string[] args)
    {
        var tcs = new TaskCompletionSource<object>();

        var task = SomethingAsync(tcs);

        Console.WriteLine("Hello");
        tcs.TrySetResult(null);

        task.Wait();
    }

    private static async Task SomethingAsync(TaskCompletionSource<object> tcs)
    {
        await tcs.Task;

        Console.WriteLine("World");
    }
}

@Tuatan, try to add additional Console.Readline() methods after each line and check number of threads in Windows Task Manager
After this try same under linux :)
Sure things like http://mattwarren.org/2017/02/07/The-68-things-the-CLR-does-before-executing-a-single-line-of-your-code/ must be here