A protocol defining methods that
URLSession instances call on their delegates to handle session-level events, like session life cycle changes.
- iOS 7.0+
- macOS 10.9+
- tvOS 9.0+
- watchOS 2.0+
In addition to the methods defined in this protocol, most delegates should also implement some or all of the methods in the
URLSession protocols to handle task-level events. These include events like the beginning and end of individual tasks, and periodic progress updates from data or download tasks.