You don't have to understand it, but you should be able to extract data from it.
Ported bit by bit.
I mean, it's what you asked it to do.
It used to be there because PropertyValue started out as the fundamental variant type before shifting focus to being the fundamental boxed type.
If all you're doing is setting properties, you can do it any way you like.
cheap_steady_clock faster than std::chrono::high_resolution_clock ?
It's quite a bit faster, though maybe you don't care.
You're always a year away.
Just for fun.
If the callback requires copyability.
Passing the obligation onward.