C# Singleton pattern with triggerable initialization

Question

I need a singleton that:

• is lazy loaded
• is thread safe
• loads some values at construction
• those values can be queried at any time

Answer 1

The first idea I had was to just use a throwaway variable assigned to the singleton's instance, which would (probably?) trigger the initialization

static Main() 
{
    var unused = Singleton.Instance;
    //this should initialize the singleton, unless the compiler optimizes it out.
    //I wonder if the compiler is smart enough to see this call has side effects.

    var vals = Singleton.Instance.Values;
}

... but programming by side-effects is something I try hard to avoid, so let's make the intention a bit clearer.

public class Singleton {
    public static void Initialize() {
        //this accesses the static field of the inner class which triggers the private Singleton() ctor.  
        Instance._Initialize();
    }
    private void _Initialize()
    { //do nothing
    }

    [the rest as before]
}

so the usage would be:

static Main() 
{
    //still wondering if the compiler might optimize this call out
    Singleton.Initialize();

    var vals = Singleton.Instance.Values;
}

Btw this would also work:

static Main() 
{
    var vals = Singleton.Instance.Values;
}

Compiler optimization aside, I think this deals with all the requirements.