Support for type hints

It’d be really nice to be able to use mypy against files that include aiofiles, but that’s not possible now since aiofiles isn’t typed.

A simple example shows that mypy --strict doesn’t allow use of aiofiles.open:

$ mypy --strict main.py 
main.py:13: error: Call to untyped function "open" in typed context

Here’s the code:

#!/usr/bin/env python
import aiofiles
import asyncio

def main() -> None:
    el = asyncio.get_event_loop()
    el.run_until_complete(async_main())

async def async_main() -> None:
    async with aiofiles.open('test_aiofiles', 'wb') as f:
        await f.write(b'Hello, world!\n')

if __name__ == '__main__':
    main()

[graingert]

It would be more convenient if you merged them in and added a py.typed

[vbraun]

types-aiofiles is a nice first step but rather incomplete