Function kill_with_fallback 

pub fn kill_with_fallback(
    helper: &mut Command,
    pid: u32,
    timeout: Duration,
    fallback: impl FnOnce(u32) -> bool,
) -> Option<String>

Run a kill helper (e.g. taskkill) bounded by timeout. When it cannot finish (it overran, or could not start) fallback(pid) runs instead (TerminateProcess on Windows) and a note for the run log is returned; None means the helper finished. Never blocks longer than timeout plus the helper reap.