fileio.py

# in asyncio:

class asyncio.AbstractFileIOImplementation:

    async def open(self):
         raise NotImplementedError

async def open(...):
    return await get_current_loop(). get_file_io_implementation().open(...)


# in uvloop or twisted or ...:

class uvloop.FileIO(asyncio.AbstractFileIOImplementation):
    # ... implementation of "open()"

class uvloop.Loop(uvloop.FileIO):
    def get_file_io_implementation(self):
        return self


# later in user code:

async def main():
    file = await asyncio.open(...)