pad() method for streams

I’m considering adding a method with this signature to Iterable:

    {Element|Padded+} pad<Padded>(Padded element)
            => let (stream=this)
            object satisfies {Element|Padded*} {
                iterator() => object satisfies Iterator<Element|Padded> {
                    value it = stream.iterator();
                    next() => if (!is Finished next = it.next()) then next else element;
                };
            };

Thoughts?

[gavinking]

Perhaps it could be called extend().

[gavinking]

Also, this can’t be called pad. String already has a pad

Sure.