Can not run example, possibly event loop policy issue

[smlrcheck]

I've tried to run the example as in the description. I'm using Python 3.7 and got error as below. I've googled a bit and it seems like event loop policy issue but I am not 100% sure.

(venv) C:\PycharmProjects\asyncio-example>python agent.py "sleep 3" http://localhost:5000
params: ['sleep', '3']
Traceback (most recent call last):
File "agent.py", line 86, in
cli()
File "agent.py", line 82, in cli
asyncio.run(main(command_parts, args.tracking_url, args.heartbeat_period))
File "C:\Program Files\Python37\lib\asyncio\runners.py", line 43, in run
return loop.run_until_complete(main)
File "C:\Program Files\Python37\lib\asyncio\base_events.py", line 568, in run_until_complete
return future.result()
File "agent.py", line 55, in main
final_status = await run(command)
File "agent.py", line 18, in run
process = await asyncio.create_subprocess_exec(*command)
File "C:\Program Files\Python37\lib\asyncio\subprocess.py", line 217, in create_subprocess_exec
stderr=stderr, **kwds)
File "C:\Program Files\Python37\lib\asyncio\base_events.py", line 1516, in subprocess_exec
bufsize, **kwargs)
File "C:\Program Files\Python37\lib\asyncio\base_events.py", line 444, in _make_subprocess_transport
raise NotImplementedError
NotImplementedError

[acroz]

Hmm, looks likely that this is due to running on Windows - I have only tested this on Unix. In the asyncio documentation, it says:

The default asyncio event loop implementation on Windows does not support subprocesses. Subprocesses are available for Windows if a ProactorEventLoop is used. See Subprocess Support on Windows for details.

It looks like on Windows, on Python 3.7 and earlier, you need to configure asyncio to use a different event loop:

https://docs.python.org/3.7/library/asyncio-platforms.html#subprocess-support-on-windows

If you set this event loop policy in agent.py, does it fix the issue? If so, I will add a note to the README.