code: protected InterleavedInputStream createInterleavedInputStream(InputStream in,
        int metaDataBlockLength, int dataBlockLength,
        SimpleSeekableFormat.MetaDataConsumer consumer) {
      return new InterleavedInputStream(in, metaDataBlockLength, dataBlockLength, consumer);
    }
docs: This factory method can be overwritten by subclass to provide different behavior.
  It's only called in the constructor.