Returns the application-defined context of an object.
- iOS 4.0+
- macOS 10.6+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
This parameter cannot be
The context of the object; can be
Your application can associate custom context data with the object, to be used only by your application. Your application must allocate and deallocate the data as appropriate.