Adds a credential to the credential storage for the specified protection space.
- iOS 2.0+
- macOS 10.2+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
The credential to add. If a credential with the same user name already exists in
credentialreplaces the existing object.
The protection space to which to add the credential.
If the credential is not yet in the set for the protection space, it will be added to it.
If you override this method, also override