fn spec_extend(&mut self, mut iterator: IntoIter<T>) {
        unsafe {
            self.append_elements(iterator.as_slice() as _);
        }
        iterator.ptr = iterator.end;
    }
A draining iterator for `Vec<T>`.

This `struct` is created by [`Vec::drain`].
See its documentation for more.

# Example

```
let mut v = v
benchmarks/haystacks/code/rust-library.rs