When sending telemetry messages from a device to the following MQTT topic:

devices/<MY_DEVICE>/messages/events/%24.uid=<MY_UID>&%24.ct=application%2Fjson&%24.ce=utf-8&%24.ctime=<SOME_TIME>

With actual values for <...> and routing them to a service bus topic I can retrieve them using the Azure Python SDK which spits out instances of azure.servicebus.ServiceBusReceivedMessage (see the documentation).

These object contain most of the information I’m interested in, e.g. content_type is correctly set to "application/json" and application_properties contains iothub-connection-device-id and iothub-creation-time-utc. However there seems to be no way to access:

• user-id
• content-encoding
• Something like iothub-message-source that indicates that this is a telemetry message.

This seems very strange to me, if this is not possible in general that would mean a backend application had no way of knowing what IoT Hub a telemetry message comes from, how it is encoded or that it is telemetry at all (and not say, a device twin change message), making the SDK almost useless.

Is there information I am missing?