> Is it simply combining stream reader and stream writer into a single object and changing the write() function to always wait the write (thus deprecating drain) and that's it?

Pretty much. We might also rename a few APIs here and there, like "close()" should become an "async def aclose()"

We also will likely want to define a few ABCs.

Which brings me to the most important point: what we need it not coding it (yet), but rather drafting the actual proposal and posting it to https://discuss.python.org/c/async-sig/20.  Once a formal proposal is there we can proceed with the implementation.

It's a bit of a process to follow, but we have to do it this way.