Thread currentThread = Thread.currentThread();
      String originalName = currentThread.getName();
      currentThread.setName("Crawler " + url);
      try {
        fetch(url);
      } catch (IOException e) {
        System.out.printf("XXX: %s %s%n", url, e);
      } finally {
        currentThread.setName(originalName);
      }
    }
  }

  public void fetch(HttpUrl url) throws IOException {