}
      return bufferedSource;
    }

    private Source source(Source source) {
      return new ForwardingSource(source) {
        long totalBytesRead = 0L;

        @Override public long read(Buffer sink, long byteCount) throws IOException {
          long bytesRead = super.read(sink, byteCount);
          // read() returns the number of bytes read, or -1 if this source is exhausted.

    private RequestBody gzip(final RequestBody body) {
      return new RequestBody() {
        @Override public MediaType contentType() {
          return body.contentType();
        }

        @Override public long contentLength() {
          return -1; // We don't know the compressed length in advance!
        }

        @Override public void writeTo(BufferedSink sink) throws IOException {

      @Override public EventListener create(Call call) {
        long callId = nextCallId.getAndIncrement();
        System.out.printf("%04d %s%n", callId, call.request().url());
        return new PrintingEventListener(callId, System.nanoTime());
      }
    };

    final long callId;
    final long callStartNanos;

    PrintingEventListener(long callId, long callStartNanos) {
      this.callId = callId;

    @Override public Response intercept(Chain chain) throws IOException {
      long t1 = System.nanoTime();
      Request request = chain.request();
      logger.info(String.format("Sending request %s on %s%n%s",
          request.url(), chain.connection(), request.headers()));
      Response response = chain.proceed(request);

      long t2 = System.nanoTime();
      logger.info(String.format("Received response for %s in %.1fms%n%s",

  }

  private static final class PrintingEventListener extends EventListener {
    long callStartNanos;

    private void printEvent(String name) {
      long nowNanos = System.nanoTime();
      if (name.equals("callStart")) {
        callStartNanos = nowNanos;
      }
      long elapsedNanos = nowNanos - callStartNanos;
      System.out.printf("%.3f %s%n", elapsedNanos / 1000000000d, name);
    }

  public void run() throws Exception {
    Request request = new Request.Builder()
        .url("http://httpbin.org/delay/2") // This URL is served with a 2 second delay.
        .build();

    final long startNanos = System.nanoTime();
    final Call call = client.newCall(request);

    // Schedule a job to cancel the call in 1 second.
    executor.schedule(() -> {

  public static void main(String[] args) throws IOException {
    if (args.length != 2) {
      System.out.println("Usage: Crawler <cache dir> <root>");
      return;
    }

    int threadCount = 20;
    long cacheByteCount = 1024L * 1024L * 100L;

    Cache cache = new Cache(new File(args[0]), cacheByteCount);
    OkHttpClient client = new OkHttpClient.Builder()
        .cache(cache)
        .build();