code: @Override
    public List<String> listBucketNames()
        throws IOException {
      logger.atFine().log("listBucketNames()");
      List<Bucket> allBuckets = listBucketsInternal();
      List<String> bucketNames = new ArrayList<>(allBuckets.size());
      for (Bucket bucket : allBuckets) {
        bucketNames.add(bucket.getName());
      }
      return bucketNames;
    }
docs: See {@link GoogleCloudStorage#listBucketNames()} for details about expected behavior.