Open-source, scalable, and fault-tolerant MQTT broker able to handle 4M+ concurrent client connections, supporting at least 3M messages per second throughput per single cluster node with low latency delivery. The cluster mode supports more than 100M concurrently connected clients.
Is your feature request related to a problem? Please describe.
Need MQTT 5 feature - Request-Response Pattern.
https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901252