@Override
    public String toString() {
        return "DefaultPlcSubscriptionTag{" +
            "plcSubscriptionType=" + plcSubscriptionType +
            ", plcTag=" + plcTag +
            ", duration=" + duration +
            '}';
    }
special {@link PlcTag} which adds a {@link PlcSubscriptionType}.
plc4j/spi/src/main/java/org/apache/plc4x/java/spi/model/DefaultPlcSubscriptionTag.java