@Override
        public boolean onBeforeUnloadDialog(CefBrowser browser, String message_text, boolean is_reload, CefJSDialogCallback callback) {
          return myJSDialogHandler.handleBooleanFirst(browser, handler -> {
            return handler.onBeforeUnloadDialog(browser, message_text, is_reload, callback);
          });
        }
@Override
        public boolean onBeforeUnloadDialog(CefBrowser browser, String message_text, boolean is_reload, CefJSDialogCallback callback)