The progress object to use for updating the progress view.
- iOS 9.0+
- Mac Catalyst 13.0+
- tvOS 9.0+
When this property is set, the progress view updates its progress value automatically using information it receives from the
NSProgress object. (Progress updates are animated.) Set the property to
nil when you want to update the progress manually. The default value of this property is
For more information about configuring a progress object to manage progress information, see