Implementation of the WTF-8 encoding.
This library uses Rust’s type system to maintain
&str types do for UTF-8.
Since WTF-8 must not be used for interchange, this library deliberately does not provide access to the underlying bytes of WTF-8 strings, nor can it decode WTF-8 from arbitrary bytes. WTF-8 strings can be obtained from UTF-8, UTF-16, or code points.