using System;

using System.Threading;

using System.Threading.Tasks;

public class Program

{

    public void Main()

    {

        Parallel.For(0, 100, i => { Singleton.Instance.GetType(); });

    }

}

​

public class Singleton

{

    private Singleton() { Console.WriteLine("Test"); }

    static Singleton()

    {

        Interlocked.CompareExchange(ref Instance, new Singleton(), null);

    }

​

    public static readonly Singleton Instance;

}