Implemented by a core service implementationsthat require notification when they are discarded. This interface is only used by the {@link org.apache.hivemind.impl.servicemodel.ThreadedServiceModel threaded service model}, which creates a service for a short period, then discards it when notified by the {@link org.apache.hivemind.service.ThreadEventNotifier}.
The service instance will be discarded regardless; this interface allows the core service implementation to know immediately when this happens, so that it can release any acquired resources.
@author Howard Lewis Ship