Function searcher_kind_empty 

unsafe fn searcher_kind_empty(
    _searcher: &Searcher,
    _prestate: &mut PrefilterState,
    _haystack: &[u8],
    _needle: &[u8],
) -> Option<usize>

Reads from the empty field of SearcherKind to handle the case of searching for the empty needle. Works on all platforms.

Safety

Callers must ensure that the searcher.kind.empty union field is set.