toAddresses = StringUtil.EMPTY_STRINGS;
                }
                final NotificationHelper notificationHelper = ComponentUtil.getNotificationHelper();
                SMailCallbackContext.setPreparedMessageHookOnThread(notificationHelper::send);
                CrawlerPostcard.droppedInto(postbox, postcard -> {
                    postcard.setFrom(fessConfig.getMailFromAddress(), fessConfig.getMailFromName());