Is MqttClient thread-safe?

[afshin-pir-GGL]

Hi,

Is calling different methods of MqttClient thread-safe? Or do I need to use a Mutex for calling methods (e.g. publishing from different thread on single instance of MQttClient)?

[afshin-pir-GGL]

I saw Send + Sync trait for `MqttClientTrait, so I should be ok.