Can anybody provide an example of using AWS IoT device shadow and also sending / receiving arbitrary messages on different topics?

My goal is

I would like to use AWS IoT to keep the physical device I’m creating “in sync” with a “shadow” in IoT Core. I am using the C API, and this part was fairly easy and is working in my project currently.

BUT, I would also like to send and receive messages to arbitrary channels over MQTT with AWS IoT. My understanding (which is limited I admit) is that AWS IoT shadow related messages are basically “normal” MQTT messages, they’re just on certain topics and with certain payloads. Using the AWS console it’s possible to send messages to other topics (e.g. “blah/blah” or whatever). But I’m ont sure on the MongooseOS / firemware side how I can do both.

The C/C++ docs (which by the way, I can’t find… there used to be more than https://mongoose-os.com/docs/mongoose-os/api/cloud/aws.md ?) have examples of setting up callbacks when messages come in, but I don’t see anything about how to send arbitrary messages over MQTT with AWS IoT.

Any advice / examples / etc?

Thank you!