asyncio.exceptions.CancelledError

Hey, I am trying to run multiple datas example (https://github.com/alpacahq/alpaca-backtrader-api/blob/master/sample/strategy_multiple_datas.py) using [alpaca-proxy-agent](https://github.com/shlomikushchi/alpaca-proxy-agent) project and I have the following error in IDE:

```
2020-10-07 16:36:52,693 code = 1000 (OK), no reason
Exception in thread Thread-7:
Traceback (most recent call last):
File "\AppData\Local\Programs\Python\Python38\lib\threading.py", line 932, in _bootstrap_inner
self.run()2020-10-07 16:36:52,708 connected to: wss://paper-api.alpaca.markets/stream

File "\AppData\Local\Programs\Python\Python38\lib\threading.py", line 870, in run
self._target(*self._args, **self._kwargs)

File "\BackTradeAlpacaMultipleData\venv\lib\site-packages\alpaca_backtrader_api\alpacastore.py", line 703, in _t_streaming_prices
streamer.run()

File "\BackTradeAlpacaMultipleData\venv\lib\site-packages\alpaca_backtrader_api\alpacastore.py", line 145, in run
self.conn.run(channels)

File "\BackTradeAlpacaMultipleData\venv\lib\site-packages\alpaca_trade_api\stream2.py", line 293, in run
loop.run_until_complete(self.consume())

File "\AppData\Local\Programs\Python\Python38\lib\asyncio\base_events.py", line 616, in run_until_complete
return future.result()

asyncio.exceptions.CancelledError
```

Log from the Docker container:
```
alpaca-proxy_1 | < {'action': 'authenticate', 'data': {'key_id': '123', 'secret_key': '456'}}
alpaca-proxy_1 | < {'action': 'listen', 'data': {'streams': ['alpacadatav1/Q.AAPL']}}
alpaca-proxy_1 | < {'action': 'authenticate', 'data': {'key_id': '123', 'secret_key': '456'}}
alpaca-proxy_1 | < {'action': 'listen', 'data': {'streams': ['alpacadatav1/Q.GOOG']}}
alpaca-proxy_1 | 'NoneType' object has no attribute 'send'
alpaca-proxy_1 | Done
alpaca-proxy_1 | 2020-10-07 20:36:52,130 root connected to: wss://data.alpaca.markets/stream
```
I am using proper **key_id** and **sekter_key**

If restart multiple datas example without stopping a proxy container, then I don't see errors anymore, but strategy never executes `next()`

Versions:
alpaca-backtrader-api-0.11.0
alpaca-trade-api-0.50.1
alpaca-proxy-agent-0.5.5

Running code on Windows 10