Associates an application-defined context with the object.
- iOS 4.0+
- macOS 10.6+
- UIKit for Mac 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
This parameter cannot be
The new application-defined context for the object. This 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.