Unable to add crumb token to payload with h2o2 proxy about crumb HOT 3 OPEN

server.route({
  method: ['*'],
  path: '/proxy/{path*}',
  handler: {
    proxy: {
      passThrough: true,
      mapUri: (request) => {
        return {
          uri: urlJoin(options.url, request.path, request.url.search),
        };
      },
      async onResponse(err, res, request, h) {
        if (err) {
          return h.response(err);
        }

        const response = h.response(res);

        response.headers = res.headers;
        response.header('X-CSRF-Token', request.plugins.crumb); // add csrf token header for restful crumb usage

        return response;
      },
    },
  },