/// This the primary pre-UTF-8 encoding for Japanese email. It uses the ASCII
/// byte range to encode non-Basic Latin characters. It's the only encoding
/// supported by this crate whose encoder is stateful.
///
/// [Index visualization](https://encoding.spec.whatwg.org/jis0208.html),
/// [Visualization of BMP coverage](https://encoding.spec.whatwg.org/jis0208-bmp.html)
///
/// This encoding roughly matches the Windows code page 50220. Notably, Windows
/// uses U+30FB in place of the REPLACEMENT CHARACTER and otherwise differs in
/// error handling.