TypeError: cannot pickle 'weakref' object

[gogobd]

I'm getting a TypeError in .../airplay/airplay.py, line 230, in events; self.event_monitor.start()

This error happens in Python 3.9.6, if I'm interpreting the logs right it's happening when the AirPlay device makes its callback to read the actual data and python-airplay wants to fork. I was trying the cli example with a downloaded Big Buck Bunny movie file: python3 cli.py --device 192.168.1.228 ../big_buck_bunny.mp4. I'm on a mac, macOS BigSur 11.3.1 i.e. Python 3.9.6 (default, Jun 29 2021, 05:25:02) [Clang 12.0.5 (clang-1205.0.22.9)] on darwin.