What is this?

Simple benchmarks of Rust (standard library) features.

• option_cardinality: various ways to convert a boolean to an integer listed under a stackoverflow question, in particular for converting Option::is_some into the number of elements in an Option container.
• option_unwrap: various ways to unwrap an option when you are sure it cannot be empty.
• btreeset_binary_contains vs btreeset_binary_contains_if_not_empty: when sets are quite likely to be empty, !set.is_empty() && set.contains(elementt) used to be faster than set.contains(element) on its own.
• btreeset_general_contains vs btreeset_general_contains_if_not_empty: found the equilibrium where this trick evens out.
• btreeset_iter vs btreeset_range: creating an iterator takes longer than creating a range, that is kind of a pair of iterators. Which is solved in issue #62924, except that the numbers say it isn't!? To be continued...

How to run this?

rustup install nightly
rustup run nightly cargo bench