code: @Override
      public final SessionDestroyedListener addingService(ServiceReference<SessionDestroyedListener> serviceReference) {
          if (LOGGER.isDebugEnabled()) {
              LOGGER.debug("Listener [" + serviceReference + "] has been added.");
          }
  
          final SessionDestroyedListener listener = context.getService(serviceReference);
          handler.addListener(listener);
  
          return listener;
      }
docs: {@inheritDoc}
  
  Adding service.
  @see ServiceTracker#addingService(ServiceReference)