Integer[] codePoints = utf8Lengths.keySet().toArray(new Integer[] {});
    StringBuilder sb = new StringBuilder();
    Random rnd = new Random();
    for (int trial = 0; trial < 100; trial++) {
      sb.setLength(0);
      int utf8Length = 0;
      for (int i = 0; i < 6; i++) {
        Integer randomCodePoint = codePoints[rnd.nextInt(codePoints.length)];
        sb.appendCodePoint(randomCodePoint);

	if retryAttempts <= 0 {
		retryAttempts = batchKeyRotateJobDefaultRetries
	}
	delay := job.KeyRotate.Flags.Retry.Delay
	if delay <= 0 {
		delay = batchKeyRotateJobDefaultRetryDelay
	}

	rnd := rand.New(rand.NewSource(time.Now().UnixNano()))

	selectObj := func(info FileInfo) (ok bool) {
		if r.Flags.Filter.OlderThan > 0 && time.Since(info.ModTime) < r.Flags.Filter.OlderThan {