One of my favorite features of this crate is the RegexSet [0] type. It can be useful to check input against a set in O(mn) time and still have the flexibility of a regex. (m is the size of the RegexSet and n is the length of the text you are searching)

Congratulations on the release!

[0]: https://docs.rs/regex/1.0.0/regex/struct.RegexSet.html