Conform AspectIdentifier to AspectToken

[zats]

If I'm not mistaken AspectIdentifier is what being returned by aspect_hookSelector… method If so it's advertised that it would conform to AspectToken protocol It does it in informal way (by just implementing required methods) What it means is that if we check the object returned by aspect_hookSelector… method at runtime for the protocol conformance it will actually fail which can impact user logic relying on that