public static ClickHouseEnumValue ofNull(ClickHouseValue ref, ClickHouseEnum type) {
        return ref instanceof ClickHouseEnumValue ? ((ClickHouseEnumValue) ref).set(true, 0)
                : new ClickHouseEnumValue(type, true, 0);
    }
Update given value to null or create a new instance if {@code ref} is null.

@param ref  object to update, could be null
@param type enum type, null is same as {@link ClickHouseEnum#EMPTY}
@return same object as {@code ref} or a new instance if it's null
clickhouse-data/src/main/java/com/clickhouse/data/value/ClickHouseEnumValue.java