Two quick questions regarding `GroupedIterator`:1) Although `GroupedIterator` has type `Iterator[Seq[A]]`, the signature of its `next` method returns a `List[A]`. Is it safe to rely on this behavior or could that change without notice?
2) Classes like `GroupedIterator` are defined to `extend AbstractIterator[A] with Iterator[A]`. What's the point of `with Iterator[A]`? Wouldn't the class be the same without it?