code: function getStatus(url, callback) {
    var client = new HttpClient(url);
    var executor = new Executor(client);
    var command = new Command(CommandName.GET_SERVER_STATUS);
    executor.execute(command, function(err, responseObj) {
      if (err) return callback(err);
      try {
        checkResponse(responseObj);
      } catch (ex) {
        return callback(ex);
      }
      callback(null, responseObj['value']);
    });
  }
docs: Queries a WebDriver server for its current status.
  @param {string} url Base URL of the server to query.
  @param {function(Error, *=)} callback The function to call with the
  response.