Fastest MQTT Client Lib

Hello,

Is there a faster mqtt client than marvinroger/async-mqtt-clien for ES8266?

I have a battery powered project. But somehow the MQTT client feels slow.
My current timings:

21:09:04.209 -> start
21:09:04.350 -> bme650 data read in
21:09:04.489 -> Wifi connected
21:09:06.352 -> Connected to MQTT.
21:09:06.399 -> Publishing packages
21:09:06.399 -> Packages published: 1
21:09:06.772 -> Packages published: 2
21:09:07.282 -> Packages published: 3
21:09:07.282 -> stop

it takes ~300ms to connect to the wifi but 1s 900ms to connect to the mqtt broker.
(broker is connected via Ethernet, ping 4ms , qos 1).

most popular is the PubSubClient library

PubSub doesn't support qos 1. But this doesn't seem to be a problem, if I flush the tcp channel. The mqtt connection time is still at 1s 800ms. At least the publishing is now a lot faster.

17:13:23.376 -> start
17:13:23.509 -> bme650 data read in
17:13:23.650 -> Wifi connected
17:13:25.461 -> connected mqtt
17:13:25.461 -> publish mqtt
17:13:25.481 -> flushed mqtt
17:13:25.508 -> stop