pub trait ListModelExtManual: Sized {
// Required methods
fn snapshot(&self) -> Vec<Object>;
fn iter<T: IsA<Object>>(&self) -> ListModelIter<'_, T>;
}
Get an immutable snapshot of the container inside the ListModel.
Any modification done to the returned container Vec will not be
reflected on the ListModel.
If T::static_type().is_a(self.item_type()) then it returns an iterator over the ListModel elements,
else the types are not compatible and returns an Err(...).
Panics if T::static_type().is_a(self.item_type()) is not true.