Looking over Ruffle's (reimplementation of Flash in Rust) "wstr" component I see...
* Lookuptable for converting between upper & lower case.
* Some light abstractions for the public API.
* Utilities for iterating over UTF-8 or UTF-16 strings.
* Utils for taking slices of strings.
* A testsuite.
* Parsing numbers.
* Iterate over a string to find matching indices, producing an iterator.
* Abstraction around a byte-array, to prepare widestrings in.
1/2!