Support uvicorn + fastapi

Uvicorn runs server in event loop and backoff raises TypeError

Traceback (most recent call last):
  File "/Users/sergey/projects/nuc-gateway/venv/bin/uvicorn", line 11, in <module>
    load_entry_point('uvicorn==0.8.4', 'console_scripts', 'uvicorn')()
  File "/Users/sergey/projects/nuc-gateway/venv/lib/python3.7/site-packages/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "/Users/sergey/projects/nuc-gateway/venv/lib/python3.7/site-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "/Users/sergey/projects/nuc-gateway/venv/lib/python3.7/site-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/Users/sergey/projects/nuc-gateway/venv/lib/python3.7/site-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/Users/sergey/projects/nuc-gateway/venv/lib/python3.7/site-packages/uvicorn/main.py", line 258, in main
    run(**kwargs)
  File "/Users/sergey/projects/nuc-gateway/venv/lib/python3.7/site-packages/uvicorn/main.py", line 279, in run
    server.run()
  File "/Users/sergey/projects/nuc-gateway/venv/lib/python3.7/site-packages/uvicorn/main.py", line 307, in run
    loop.run_until_complete(self.serve(sockets=sockets))
  File "uvloop/loop.pyx", line 1451, in uvloop.loop.Loop.run_until_complete
  File "/Users/sergey/projects/nuc-gateway/venv/lib/python3.7/site-packages/uvicorn/main.py", line 314, in serve
    config.load()
  File "/Users/sergey/projects/nuc-gateway/venv/lib/python3.7/site-packages/uvicorn/config.py", line 186, in load
    self.loaded_app = import_from_string(self.app)
  File "/Users/sergey/projects/nuc-gateway/venv/lib/python3.7/site-packages/uvicorn/importer.py", line 20, in import_from_string
    module = importlib.import_module(module_str)
  File "/Users/sergey/.pyenv/versions/3.7.3/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "./app/api_app.py", line 14, in <module>
    from app.api import api_v1
...
  File "./app/itm/client.py", line 142, in <module>
    class APIClient(requests_client.Client):
  File "./app/itm/client.py", line 450, in APIClient
    @retry401
  File "/Users/sergey/projects/nuc-gateway/venv/lib/python3.7/site-packages/backoff/_decorator.py", line 181, in decorate
    "backoff.on_exception applied to a regular function "
TypeError: backoff.on_exception applied to a regular function inside coroutine, this will lead to event loop hiccups. Use backoff.on_exception on coroutines in asynchronous code.

[smagafurov]

My current ugly workaround:

import backoff
backoff._decorator._is_event_loop = lambda: False

[bgreen-litl]

Okay! This makes more sense to me. I think it may be fine to remove the check all together then. I will look into doing this.