str_trim_ascii_whitespace.rs

const fn str_trim_ascii_whitespace(s: &str) -> &str {
    let mut bs = s.as_bytes();

    while let Some((hd, tl)) = bs.split_first() {
        if hd.is_ascii_whitespace() {
            bs = tl;
        } else {
            break;
        }
    }

    while let Some((tl, hd)) = bs.split_last() {
        if tl.is_ascii_whitespace() {
            bs = hd;
        } else {
            break;
        }
    }

    match std::str::from_utf8(bs) {
        Ok(s) => s,
        Err(_) => unreachable!(),
    }
}