There's two sets of missing things here. The first is interfaces to represent async versions of existing core sync traits (that's the AsyncRead/AsyncWrite/Stre

There's two sets of missing things here. The first is interfaces to represent async versions of existing core sync traits (that's the AsyncRead/AsyncWrite/Stream/Sink/etc. you refer to). What makes this somewhat awkward is you're providing these traits without an implementation of them in the standard lib. The other thing that's missing is something like GlobalAlloc. You need a generic executor runtime interface to handle some of the executor things you need like "schedule new task". In general, I think there's a class of features where you need to have just one global (really, process-wide, not just library-wide) provider of some service, and it may be worth having language features to provide this functionality. Memory allocation is one specific area; async executors is another topical area. But you can also throw in stuff like signal handlers or logging or service providers or error handling or tracing features, etc.