(PHP 5 >= 5.1.0, PHP 7)
XMLReader::moveToElement — Position cursor on the parent Element of current Attribute
Moves cursor to the parent Element of current Attribute.
Returns TRUE if successful and FALSE if it fails or not positioned on
Attribute when this method is called.
On an element like this: <self_closing attribute="1" /> isEmptyElement will return FALSE after you have iterated through the attributes. So you need to use implicitly call moveToElement(), in order to move the cursor back to the parent element and use isEmptyElement again.