public static void releaseKryo(Kryo kryo) {
    if (kryo != null){
      ((KryoWithHooks) kryo).restore();
    }
    kryoPool.free(kryo);
  }
Release kryo instance back to the pool.

@param kryo - kryo instance to be released
ql/src/java/org/apache/hadoop/hive/ql/exec/SerializationUtilities.java