code: function downloadString(url) {
    return new Promise((resolve, reject) => {
      request({
        url,
        // We want to force Cloudfront to serve us the latest file.
        headers: {
          'Accept-Encoding': 'gzip, deflate',
        },
      }, (error, response, body) => {
        if (!error && response.statusCode === 200) {
          resolve(body);
        } else {
          reject(error || response.statusCode);
        }
      });
    });
  }
docs: /* istanbul ignore next