docs: @Override
      protected IQChildElementXmlStringBuilder getIQChildElementBuilder(IQChildElementXmlStringBuilder str) {
          str.attribute("sid", sid);
          str.rightAngleBracket();
  
          if (bridgeAction.equals(BridgeAction.create))
              str.append("<candidate/>");
          else if (bridgeAction.equals(BridgeAction.change))
              str.append("<relay ").append(getAttributes()).append(" />");
          else
              str.append("<publicip ").append(getAttributes()).append(" />");
  
          return str;
      }