code: public Iterable<Result<Item>> listObjects(final String bucketName, final String prefix)
      throws XmlPullParserException {
      // list all objects recursively
      return listObjects(bucketName, prefix, true);
    }
docs: Lists object information in given bucket and prefix.
  
  @param bucketName Bucket name.
  @param prefix     Prefix string.  List objects whose name starts with `prefix`.
  
  @return an iterator of Result Items.
  
  @throws XmlPullParserException      upon parsing response xml