code: static BlockMetadataHeader readHeader(File file) throws IOException {
      DataInputStream in = null;
      try {
        in = new DataInputStream(new BufferedInputStream(
                                 new FileInputStream(file)));
        return readHeader(in);
      } finally {
        IOUtils.closeStream(in);
      }
    }
docs: Reads header at the top of metadata file and returns the header.
  
  @param dataset
  @param block
  @return
  @throws IOException