1. Trio has *stappled* streams for the case, especially useful for starting TLS session over stdin/stdout.
We can master something too.
2. FlowControlMixin was always considered a **private** API. Would be nice to add an underscore prefix to the name if not too late. IIRC the official policy is: if you need the class -- copy and paste it into your project.
3. Even a person with very many stars on StackOverflow doesn't become an asyncio expert automatically; while I very respect the sie and so on.