Google Cloud Pub/Sub pull mode

I am currently testing the Google Cloud PubSub input plugin for telegraf and I am wondering how I can access the message attribute keys.

No problems accessing the message body and all the keys, but trying to get the Cloud IoT Core authenticated deviceId from the message attributes seems to be impossible, Is this a limitation in pull mode and do I need to switch to push mode?

did you ever figure this out? same issue. Seems obvious the attributes should be available