code: function(serverUrl) {
    var parsedUrl = url.parse(serverUrl);
    if (!parsedUrl.hostname) {
      throw new Error('Invalid server URL: ' + serverUrl);
    }
  
    /**
     * Base options for each request.
     * @private {!Object}
     */
    this.options_ = {
      host: parsedUrl.hostname,
      path: parsedUrl.pathname,
      port: parsedUrl.port
    };
  }
docs: A {@link webdriver.http.Client} implementation using Node's built-in http
  module.
  @param {string} serverUrl URL for the WebDriver server to send commands to.
  @constructor
  @implements {webdriver.http.Client}