Thread-safety of event raising with null propagation [duplicate]

Question

Are these 2 samples the same? Can old-style raising be replaced with Invoke and null propagation?

OLD:

    public event EventHandler<MyEventArgs> MyEvent;
    protected virtual void OnMyEvent(MyEventArgs args)
    {
        EventHandler<MyEventArgs> handler = this.MyEvent;
        if (handler != null)
            handler(this, args);
    }

NEW:

    public event EventHandler<MyEventArgs> MyEvent;
    protected virtual void OnMyEvent(MyEventArgs args)
    {
        this.MyEvent?.Invoke(this, args);
    }

Null check is important but it is clear. What is about additional variable?
How does null-propogation work internally? Is it thread-safe with events?

P.S. Regarding thread safety in events you can read here:
C# Events and Thread Safety

Answer 1

Given this code:

    static void Main(string[] args)
    {
        var a = new Random(1).Next() > 0 ? new object() : null;
        var b = a?.GetHashCode();
        Console.WriteLine(b);
    }

This is what I see in IL representation at line where monadic operator is called in Release mode (VS 2015):

IL_0016: dup          
IL_0017: brtrue.s     IL_0025

... //nothing iteresting, just setting null to 'a' and skip IL_0025 area

IL_0025: callvirt     instance int32 [mscorlib]System.Object::GetHashCode()

Let me explain:

• dup - is command which copies current value on stack into new one placed in this stack (in this case it is simply duplicating value of 'a')
• brtrue.s - transfers control to address if value on stack is true/notnull/non-zero (as of now value is copy of 'a' - it is thread-safe to use it)

So, answer to your question is: YES, it is thread-safe to use monadic operator, because it is operating over a copy.