Delegate implementation to std::experimental

[wusatosi]

Delegate implementation detail to std::experimental.

Note that this removes support for

• apple clang
• msvc
• LLVM version < 19 (latest default stable for llvm install script is 18, this very much require the front-line release of LLVM)
• GCC version < 12

This is the complication I was complaining about in #3 .

This also means our project currently only support > C++20.

• We should document this compiler requirement

[wusatosi]

Will likely be able to add back some support once we have a switch and have alternative implementations.

This compiler requirement is pretty crazy for llvm.

[JeffGarland]

Where are we at with this PR now given that the other PR has 20 as the base?

[robert-andrzejuk]

@wusatosi I don't understand all the removals.
Do those compilers not support C++20, or do they not compile the example?

We should just remove the compilers that do not support C++20.

[wusatosi]

@wusatosi I don't understand all the removals.
Do those compilers not support C++20, or do they not compile the example?

We should just remove the compilers that do not support C++20.

The removed compilers doesn't have std::experimental

[wusatosi]

Where are we at with this PR now given that the other PR has 20 as the base?

That PR is Irrelevant to this.

[JeffGarland]

ok this looks ready to go -- lets merge it