Note, this function was intoduced in MQTTSubscribe version 3.0.
This runs MQTTSubscribe in an environment that is very close to running MQTTSubscribe with WeeWX. This serves the following purposes.
- The MQTTSubscribe configuration can be tested prior to updating the configuration (weewx.conf) being used by WeeWX.
- The MQTTSubscribe configuration can be debugged without having to update the configuration (weewx.conf) being used by WeeWX.