Subscribe RetainAsPublished misbehave with MQTT 3.1.1

[bkupidura]

Currently every message received by 3.1.1 MQTT client, will have retain flag set to false. Even when it was published with retained flag set to true.
MQTT 3.1.1 spec is not very specific about that, but previosly retain flag was set to whatever value was set in PUB packet.

This is because of https://github.com/mochi-co/mqtt/blob/0de1d731db5b4b94f580d1441560658303bdab2c/server.go#L788

AFAIK RetainAsPublished should be used only for v5 clients and for v3 it should be always set to 1

[mochi-co]

I agree. I will try to fix this tomorrow if I get a chance, and push a new release.

[mochi-co]

This should be fixed in v2.1.5, try it out and let me know 👍🏻

[bkupidura]

@mochi-co its working as expected! Thank you!