Traceback in notify_one_chunk

[oberstet]

I'm seeing this occasionally when stopping a client:

2020-04-16T08:26:47+0200 ok, echo() successfully called 1th time, answered by PID 1
2020-04-16T08:26:48+0200 ok, echo() successfully called 2th time, answered by PID 1
2020-04-16T08:26:49+0200 ok, echo() successfully called 3th time, answered by PID 1
2020-04-16T08:26:50+0200 ok, echo() successfully called 4th time, answered by PID 1
2020-04-16T08:26:51+0200 ok, echo() successfully called 5th time, answered by PID 1
2020-04-16T08:26:53+0200 ok, echo() successfully called 6th time, answered by PID 1
^C2020-04-16T08:26:53+0200 Received SIGINT, shutting down.
2020-04-16T08:26:54+0200 dropping connection to peer tcp4:52.71.32.105:443 with abort=True: WebSocket closing handshake timeout (peer did not finish the closing handshake in time)
2020-04-16T08:26:54+0200 Scheduling retry 1 to connect <twisted.internet.endpoints.SSL4ClientEndpoint object at 0x7f545eedc610> in 2.4986507909029503 seconds.
2020-04-16T08:26:54+0200 Unhandled Error
Traceback (most recent call last):
  File "backend/client.py", line 65, in <module>
    runner.run(Client, auto_reconnect=True)
  File "/home/oberstet/scm/crossbario/autobahn-python/autobahn/twisted/wamp.py", line 410, in run
    reactor.run()
  File "/home/oberstet/cpy381_5/lib/python3.8/site-packages/twisted/internet/base.py", line 1283, in run
    self.mainLoop()
  File "/home/oberstet/cpy381_5/lib/python3.8/site-packages/twisted/internet/base.py", line 1292, in mainLoop
    self.runUntilCurrent()
--- <exception caught here> ---
  File "/home/oberstet/cpy381_5/lib/python3.8/site-packages/twisted/internet/base.py", line 913, in runUntilCurrent
    call.func(*call.args, **call.kw)
  File "/home/oberstet/scm/crossbario/txaio/txaio/_common.py", line 136, in _notify_bucket
    notify_one_chunk(calls, self._chunk_size, max(0.0, delay_ms))
  File "/home/oberstet/scm/crossbario/txaio/txaio/_common.py", line 130, in notify_one_chunk
    raise RuntimeError(msg)
builtins.RuntimeError: Error(s) processing call_later bucket:
'NoneType' object has no attribute 'shutdown'


2020-04-16T08:26:54+0200 Main loop terminated.