@Override
    public boolean add(E item) {
        Long value =
                keyValMap.putIfAbsent(item, System.currentTimeMillis());
        return (value == null);
    }
ConcurrentHashSet, construct the set collection through ConcurrentHashMap
to complete the operation management of the concurrent set
inlong-manager/manager-schedule/src/main/java/org/apache/inlong/manager/schedule/airflow/util/ConcurrentHashSet.java