docs: public synchronized SiteNode addPath(HistoryReference ref) {
      	if (Constant.isLowMemoryOptionSet()) {
      		throw new InvalidParameterException("SiteMap should not be accessed when the low memory option is set");
      	}
  
          HttpMessage msg = null;
          try {
              msg = ref.getHttpMessage();
          } catch (Exception e) {
              // ZAP: Added error
              log.error(e.getMessage(), e);
              return null;
          }
          
          return addPath(ref, msg);
      }