Starting from Python 3.8 asyncio supports https://tools.ietf.org/html/rfc6555

It allows working better in dual-host configurations.
It would be nice to support it by aiohttp if the feature is available by Python version.
Perhaps passing happy_eyeballs_delay and interleave to loop.create_connection() is enough.

A volunteer is welcome!

P.S.
Ooops, parameters are even not documented by asyncio docs, need to fix it.