Gets the default credential for the specified protection space, which is being accessed by the given task, and passes it to the provided completion handler.
- iOS 8.0+
- macOS 10.10+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
The protection space of interest.
The task seeking to use the protection space
A completion handler that receives the default credential as its argument, or
nilif there is no default credential for this combination of protection space and task.