Map<String, Object> parentMap = new LinkedHashMap<>();
        DocMap docMap = new DocMap(parentMap);

        docMap.put("c_key", "value_c");
        docMap.put("a_key", "value_a");
        docMap.put("lang", "en");
        docMap.put("b_key", "value_b");

        Set<Map.Entry<String, Object>> entrySet = docMap.entrySet();

        SerializeUtil.serialize(amap);
        System.out.println("ArrayMap serialize:" + (System.currentTimeMillis() - start));
    }

    private static class MyKey {
        Object _key;

        MyKey(Object key) {
            _key = key;
        }

        @Override
        public int hashCode() {
            return 0;
        }

        @Override
        public boolean equals(Object o) {