`std::invoke` is currently quite heavy compared to a function call,
since it involves quite heavy SFINAE. This can be done significantly
more efficient by the compiler, since most calls to `std::invoke` are
simple function calls and 6 out of the seven overloads for `std::invoke`
exist only to support member pointers. Even these boil down to a few
relatively simple checks.
Some real-world testing with this patch revealed some significant
results. For example, instantiating `std::format("Banane")` (and its
callees) went down from ~125ms on my system to ~104ms.
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