def preview
      notifications = Correspondent::Notification.for_subscriber(params[:subscriber_type], params[:subscriber_id])

      if stale?(notifications)
        render(
          json: {
            count: notifications.count,
            notification: notifications.limit(1).first
          }
        )
      end
    end
def preview
      notifications = Correspondent::Notification.for_subscriber(params[:subscriber_type], params[:subscriber_id])

      if stale?(notifications)
        render(
          json: {
            count: notifications.count,
            notification: notifications.limit(1).first
          }
        )
      end
    end
preview

 Returns the newest notification and the total
 number of notifications for the given subscriber.