explicit eventloop factory in python3.13

https://docs.python.org/3/library/asyncio-eventloop.html#asyncio.EventLoop

An alias to the most efficient available subclass of AbstractEventLoop for the given platform.

Before 3.13 can be implemented with:

import asyncio
import selectors

loop = asyncio.SelectorEventLoop(selectors.SelectSelector())

EventLoop came with deprecation of the policy based event loop selection: https://docs.python.org/3/library/asyncio-policy.html#asyncio-policies