Split over an iterator in Rust

iterator_split.rs

struct Split<I, P> {
    iter: I,
    pred: P,
}

impl<I, P> Iterator for Split<I,P> where I: Iterator, P: Fn(&I::Item) -> bool {
    type Item = Vec<I::Item>;
    fn next(&mut self) -> Option<Vec<I::Item>> {
        let ref p = self.pred;
        let not_p = |x: &I::Item| !p(x);
        let mut i = self.iter.by_ref().skip_while(p).take_while(not_p);
        match i.next() {
            None    => None,
            Some(x) => {
                let mut v = Vec::new();
                v.push(x);
                v.extend(i);
                Some(v)
            }
        }
    }
}

fn split<I: Iterator, P: Fn(&I::Item) -> bool>(iter: I, pred: P) -> Split<I, P> {
    Split { iter: iter, pred: pred}
}