code: public final void resumeState(final WebDriver webDriver) {
          Validate.validState(crawlFrontier != null, "Cannot resume state at this point.");
  
          start(webDriver, true);
      }
docs: Resumes the previously loaded state using the browser specified by the given
  <code>WebDriver</code> instance. This method will block until the crawler finishes.
  
  @param webDriver the <code>WebDriver</code> instance to control the browser