Interface to be implemented by transparent resource proxies that need to be
considered as equal to the underlying resource, for example for consistent
lookup key comparisons. Note that this interface does imply such special
semantics and does not constitute a general-purpose mixin!
Such wrappers will automatically be unwrapped for key comparisons in
Only fully transparent proxies, e.g. for redirection or service lookups,
are supposed to implement this interface. Proxies that decorate the target
object with new behavior, such as AOP proxies, do not qualify here!