The two futures chained by :func:asyncio.future.wrap_future are now
symmetrical.

Before, the behaviour was:

1. When the wrapped future gets a result, the new future gets the same result,
2. When the new future is cancelled, the wrapped future is cancelled

now, these new behaviours have been implemented:
3) When the new future gets a result, the wrapped future gets the same result,
4) When the wrapped future is cancelled, the new future is cancelled

so, the new behaviour is:

1. When either one future is done, the other is done with the same results or exceptions,
2. When either one future is cancelled, the other is cancelled.

https://bugs.python.org/issue34430