[bmap](https://repos.qrnch.tech/pub/bmap)::CountedBitmap is an array of bits,
with methods to set/clear bits by index, and a built-in counter used to keep
track of how many bits have been set.
This crate has a very specific use case. You are *probably* looking for the
[bitvec](https://crates.io/crates/bitvec) crate.