Create a new iterator from an existing iterator. The new iterator
will only return those elements that match the given compare function @func.
The first parameter that is passed to @func is the #GValue of the current
iterator element and the second parameter is @user_data. @func should
return 0 for elements that should be included in the filtered iterator.
When this iterator is freed, @it will also be freed.
Create a new iterator from an existing iterator. The new iterator will only return those elements that match the given compare function @func. The first parameter that is passed to @func is the #GValue of the current iterator element and the second parameter is @user_data. @func should return 0 for elements that should be included in the filtered iterator.
When this iterator is freed, @it will also be freed.