`RuntimeError: no running event loop` after upgrading to 0.5.0

Unfortunately, changes in #246 broke the code that relies on creating an instance of janus.Queue outside of the scope of a running event loop, for no obvious reason.

Also, the behavior now contradicts with the behavior of asyncio.Queue.

>>> import asyncio
>>> asyncio.Queue()
<Queue at 0x7f76be085730 maxsize=0>

>>> import janus
>>> janus.Queue()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/user/projects/project/.venv/lib64/python3.8/site-packages/janus/__init__.py", line 29, in __init__
    self._loop = current_loop()
RuntimeError: no running event loop

Is there any good reason to not just use asyncio.get_event_loop? From performance perspective it shouldn’t be significant.

[martyanov]

Are there any proofs that asyncio.get_event_loop will be replaced with asyncio.get_running_loop in asyncio.Queue, for example? I mean this will be refactored to use asyncio.get_running_loop. Deprecating and removing the loop argement is ok, but changing the internal behavior will break a lot of people’s code.

[asvetlov]

The reason is: Queue does not exist without the loop. The current version makes this dependency strict and explicit. Sorry, this is not going to change