This is something quite similar to what I've worked on 8 years ago [1] although I gave up. I didn't have integration with other async frameworks/libs in mind from the beginning. I short, there weren't many things I could use it for. Plus it was slow - sure, there was no 'yield from' (PEP-380) back then.

It's interesting that David Beazley did it (he is certainly more qualified) but it's doomed if it doesn't play well with other libraries ...

[1] https://pypi.python.org/pypi/cogen