Function encoding_rs::ascii::basic_latin_to_ascii

pub unsafe fn basic_latin_to_ascii(
    src: *const u16,
    dst: *mut u8,
    len: usize,
) -> Option<(u16, usize)>

Safety: src and dst must have len elements, src is valid for read, dst is valid for write Safety-usable invariant: will return Some() when it fails to convert. The first value will be a u8 that is > 127.