https://github.com/fluffysquirrels/mqtt-async-client-rs
https://github.com/ntex-rs/ntex-mqtt/tree/master/src/v5/codec
https://github.com/zonyitoo/mqtt-rs   - 10 releases
https://github.com/vincentdephily/mqttest  2 releases
https://github.com/00imvj00/mqttrs  - 5 releases
	https://docs.rs/mqttrs/0.4.1/mqttrs/
Discussion:
https://www.reddit.com/r/rust/comments/g2c75e/which_mqtt_rust_library_do_you_recommend/

https://docs.rs/mqtt-protocol/0.11.0/mqtt/index.html
https://github.com/eclipse/paho.mqtt.rust
https://github.com/bytebeamio/rumqtt/tree/master/rumqttc

https://lib.rs/crates/rumqttc-async-std


Also:
https://reposhub.com/rust/deployment/messense-rust-musl-cross.html

https://github.com/ratelmq/ratelmq
https://lib.rs/crates/assert_no_alloc
https://www.infoq.com/presentations/latency-response-time/