Compiler inlines and optimizes the whole function to return 330

[jhorstmann]

Rust and its pattern matching is fast, but not that fast ;)

Rustc 1.77 seems to be able to optimize the whole pattern_matching function to the equivalent of return 330.

Rustc 1.78 seems to be able to do the same optimization also for the dynamic_dispatch version.

See https://rust.godbolt.org/z/zTrzhTbze for the assembly output.

A possible improvement to the benchmark could be to change Action to take a parameter, and to tunnel the parameter value through criterion::black_box to avoid compiler optimizations based on that value.

[tusharmath]

Thank @jhorstmann I have fixed the benchmark. Appreciate your help 🙏