pub fn iter<'a, 'h>(&'a self, haystack: &'h [u8]) -> OneIter<'a, 'h> {
        OneIter { searcher: self, it: generic::Iter::new(haystack) }
    }
Returns an iterator over all occurrences of the needle byte in the
given haystack.

The iterator returned implements `DoubleEndedIterator`. This means it
can also be used to find occurrences in reverse order.
src/arch/all/memchr.rs