[socketcluster]

https://socketcluster.io/ has had such stream implementation and backpressure management since at least 2019.

Here's the WritableConsumableStream module:

https://github.com/SocketCluster/writable-consumable-stream

SocketCluster solves the problem of maintaining message order with async processing.

This feature is even more useful now with LLMs as you can process data live, transform streams with AI with no risk of mangling the message order.

I may have been the first person to use a for-await-of loop in this way with backpressure. At least on an open source project.