@Override
    public void subscribeService(Service service, Subscriber subscriber, String clientId) {
        // Subscriber is an ephemeral type only, so call ephemeral client directly
        ephemeralClientOperationService.subscribeService(service, subscriber, clientId);
    }
@Test
    void testSubscribeService() {
        clientOperationServiceProxy.subscribeService(service, subscriber, ephemeralIpPortId);
        verify(ephemeralClientOperationServiceImpl).subscribeService(service, subscriber, ephemeralIpPortId);
        verify(persistentClientOperationServiceImpl, never()).subscribeService(service, subscriber, ephemeralIpPortId);
    }