Tells the delegate a service has disappeared or has become unavailable.
- iOS 2.0+
- macOS 10.2+
- Mac Catalyst 13.0+
- tvOS 9.0+
Sender of this delegate message.
Network service that has become unavailable.
netis waiting for additional services.
falsewhen there are no additional services.
The delegate uses this message to compile a list of unavailable services. It should wait until
false to do a bulk update of user interface elements.