> 1) The MQTT specification didn't even support message properties until 5.
> 2) The MQTT specification already has a way to deal with duplicates using
> its quality-of-service levels.
>
> Is there a use-case where using _AMQ_DUPL_ID would be preferred over using,
> for example, QoS 2?
In my setup, QoS 2 does not prevent receiving the messages twice.
MQTT client/publisher --> Artemis1 <--federation-conn1--> Artemis2 -> MQTT
client/subscriber
\ /
\--federation-conn2--/
Both federation-conn are up in parallel.
However, with the same Artemis1/2 setup, but Openwire (CMS) publisher and
subscriber, the subscriber only gets the message once,
Artemis2 reports reception of duplicate message, and drops it.
