remove docs usage of deprecated asyncio.get_event_loop

[graingert]

and update docs:

• only Python 3 is supported
• tornado.ioloop.IOLoop.current() or IOLoop().run_sync is deprecated in favour of asyncio.run
• avoid loop.run_forever in favour of await asyncio.Event().wait()
• use async with where possible

• Closes #xxxx
• Tests added / passed
• Passes pre-commit run --all-files

[graingert]

the "Either use Tornado" "Or use asyncio" is redundant now that asyncio.run is the recommended approach for starting tornado:

https://github.com/tornadoweb/tornado/blob/3de78b7a15ba7134917a18b0755ea24d7f8fde94/README.rst#hello-world

[graingert]

s.listen( was changed to be an async def so this didn't work anymore:

distributed/distributed/core.py

Lines 444 to 461 in 0b5d6eb

	async def listen(self, port_or_addr=None, allow_offload=True, **kwargs):
	if port_or_addr is None:
	port_or_addr = self.default_port
	if isinstance(port_or_addr, int):
	addr = unparse_host_port(self.default_ip, port_or_addr)
	elif isinstance(port_or_addr, tuple):
	addr = unparse_host_port(*port_or_addr)
	else:
	addr = port_or_addr
	assert isinstance(addr, str)
	listener = await listen(
	addr,
	self.handle_comm,
	deserialize=self.deserialize,
	allow_offload=allow_offload,
	**kwargs,
	)
	self.listeners.append(listener)

[github-actions]

Unit Test Results

       18 files  ±0         18 suites  ±0   10h 6m 20s ⏱️ + 11m 1s
  2 703 tests ±0    2 616 ✔️  - 5       83 💤 +2  4 ❌ +3 
24 163 runs  ±0  22 870 ✔️  - 4  1 289 💤 +2  4 ❌ +2 

For more details on these failures, see this check.

Results for commit 97206e2. ± Comparison against base commit 2ff681c.

[mrocklin]

The docs in distributed.docs.org aren't really pointed to anywhere. I'd be comfortable nuking the entire thing. I encourage you to look through docs/ in dask/dask and not spend much time improving docs in this repository. My apologies that you weren't made aware of this before.