code: @Override
      protected void enqueueNotification(final Notification not) {
          not.lastRun = System.currentTimeMillis();
          final SubscriptionSummary summary = postNotification(not.subscriber, not.mimeType, not.payload);
          not.callback.onSummaryInfo(summary);
      }
docs: A blocking call that performs a notification. If there are pending retries that are older
  than two minutes old, they will be retried before the method returns.
  
  @param not