LavinMQ::MQTT

Topics become routing keys and topic filters binding keys, both stored as AMQP short strings, so longer ones can't be written to a queue. MQTT itself allows topics up to 65535 bytes.

The QoS carried in binding arguments, the inverse of qos_arguments.

Any integer type is accepted: bindings made over the HTTP API or imported from a definitions file don't go through the MQTT protocol parser, so the header isn't necessarily a UInt8. The value is granted as the closest supported QoS, never higher than what we can deliver: QoS 2 as QoS 1 [MQTT-3.9.3-1], a missing, negative or non-integer value as QoS 0.

The binding arguments that carry the given QoS, as one of the two shared, treat-as-read-only constants above, so no table is allocated per subscription. QoS 2 isn't supported and is granted as QoS 1, hence anything above 0 maps to QOS1_ARGUMENTS.