pub fn memrnechr_tpl(buf: &[u8], by1: u8, by2: u8, by3: u8) -> Option<usize>
This is same as buf.iter().rposition(|&x| x != by1 && x != by2 && x != by3), not included libc.
buf.iter().rposition(|&x| x != by1 && x != by2 && x != by3)