Cleanup behavior

[elbaro]

If the asyncio.Future returned by this conversion is cancelled via asyncio.Future.cancel, the Rust future will be cancelled as well (new behaviour in v0.15).

When a Python future is garbage collected without completion or cancellation, will the corresponding Rust future from tokio::spawn keep running?

How about wrapping the python future in something like this?

class FutureWrap:
   ...
   def __del__(self):
      if (not done) and (not cancelled):
         cancel_signal.send()