detect-async-library.py

import types

class FakeFuture:
    _asyncio_future_blocking = True

    @property
    def _loop(self):
        import asyncio
        return asyncio.get_event_loop()

    def add_done_callback(self, fn, **kwargs):
        # **kwargs to carry context=, on asyncio's that support it
        self._loop.call_soon(fn, self, **kwargs)

    def result(self):
        pass

LIBRARY_QUERY_SENTINEL = FakeFuture()

@types.coroutine
def current_async_library():
    value = yield LIBRARY_QUERY_SENTINEL
    if value is None:
        return "asyncio"
    else:
        return value

################################################################

import asyncio

async def main():
    print(await current_async_library())

loop = asyncio.get_event_loop()
loop.run_until_complete(main())