Function rustc_lexer::unescape::unescape_byte_literal

pub fn unescape_byte_literal<F>(literal_text: &str, mode: Mode, callback: &mut F)where
    F: FnMut(Range<usize>, Result<u8, EscapeError>),

Takes a contents of a byte, byte string or raw byte string (without quotes) and produces a sequence of bytes or errors. Values are returned through invoking of the provided callback.