We'd like to use the new Message Ordering feature for Google Cloud PubSub, but for messages coming from IoT Devices hooked up to IoT Core.
The documentation states that an orderingKey should be provided when publishing the messages. Examples are provided that are straightforward enough, but seem to apply to the PubSub Client libraries, whereas we are publishing against the IoT Core API using MQTT.
Is it possible to provide an ordering key through the IoT Core MQTT bridge, and if so, how should that be specified? I couldn't find any documentation or examples on the topic.