@Override
  public void close() throws IOException {
    if (orcReader != null) {
      IOUtils.closeQuietly(orcReader);
    }
    if (encodedReader != null) {
      encodedReader.close();
    }
  }
Pre read the file footer into the cache.
llap-server/src/java/org/apache/hadoop/hive/llap/io/encoded/LlapOrcCacheLoader.java