Yeah, I tend to agree. `RowIterator` is currently using `eachWithIndex` on the `columnNames`, which suggests that it requires it to be an ordered list, and not just an `Iterable`. @mhurne and I discussed a few different options, including using a different name for the field so that it doesn't match the name of the overidden getter, or passing `columnNames as List` into the `RowIterator`. Let me know if you have a preferred approach.