code: public static ServiceAgentInfo from(SAAdvert saAdvert)
      {
          IdentifierExtension identifierExtension = IdentifierExtension.findFirst(saAdvert.getExtensions());
          String identifier = identifierExtension == null ? null : identifierExtension.getIdentifier();
          return new ServiceAgentInfo(identifier, saAdvert.getURL(), saAdvert.getScopes(), saAdvert.getAttributes(), saAdvert.getLanguage());
      }
docs: private final int port;