Advances this and retrieves the key and/or value that are now pointed to as a result of this advancement.
If false is returned, key and value are not set, and the iterator
becomes invalid.
| this |
an initialized GenericSetIter |
| key |
a location to store the key, or null |
| value |
a location to store the value, or null |
|
false if the end of the GenericSet has been reached. |