Flags the current activity as a breadcrumb, to signify an interesting event.
- iOS 9.2+
- macOS 10.11.2+
- Mac Catalyst 13.0+Beta
- tvOS 9.1+
- watchOS 2.1+
A label that describes the breadcrumb.
Use breadcrumbs to track interactions that span across multiple activities. Keep in mind that not all activities are interesting events.
This function can only be called once per activity; subsequent calls are ignored.