Having built a hobo version of something similar (serving a minimal subset of the Kafka API on top of CosmoDB): there’s also the hybrid scenario where the cheap serverless streams are used for scalability and broadcast while a low-latency core is maintained on sharply reduced compute resources. An 80/20 approach that saves a lot and, in our case, reduced cluster (mis)management risks at the same time.

In our case BLOB and large document transfers were handled in parallel, merging them together through object storage is a highly appealing package. Great work!