fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
        <Self as SpecExtend<I>>::spec_extend(self, iter);
    }
Returns the remaining items of this iterator as a slice.

# Examples

```
let vec = vec!['a', 'b', 'c'];
let mut
benchmarks/haystacks/code/rust-library.rs