How telegraf download data using mqtt_consumer.go

Hi
I don’t see how telegraf download data using mqtt_consumer.go. Can someone explain me which part of code is responsible for that? I assume that maybe telegraf is not fast enough to download all data from my mqtt broker. Do you have idea how to debug that? https://github.com/influxdata/telegraf/blob/9853bf6c54ff18ab0e14a141b7b4580a1e54976a/plugins/inputs/mqtt_consumer/mqtt_consumer.go

Telegraf uses the this library to use MQTT.
I’m not a programmer, so I just don’t know how it technically does it.

If telegraf is not fast enough you should see messages piling up in your queue, is that the case?