1This crate contains array-based data structures used by the core Cranelift code 2generator which represent a set of small ordered sets or maps. 3 4**These are not general purpose data structures that are somehow magically faster that the 5standard library's `BTreeSet` and `BTreeMap` types.** 6 7The tradeoffs are different: 8 9- Keys and values are expected to be small and copyable. We optimize for 32-bit types. 10- A comparator object is used to compare keys, allowing smaller "context free" keys. 11- Empty trees have a very small 32-bit footprint. 12- All the trees in a forest can be cleared in constant time. 13