public static ClickHouseEnumValue ofNull(Class<? extends Enum> clazz) {
        return ofNull(null, ClickHouseEnum.of(clazz));
    }
Create a new instance representing null value.

@param clazz enum class
@return new instance representing null value
clickhouse-data/src/main/java/com/clickhouse/data/value/ClickHouseEnumValue.java