Returns the reference data used to construct a given object ID.
- iOS 5.0+
- macOS 10.7+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
- Core Data
An object ID created by the receiver.
The reference data used to construct objectID.
This method raises an
invalid if the object ID was not created by the receiving store.
You should not override this method.