[Qupyter] Unloading cog sometimes hangs the bot forever on socket terminating

[Jackenmen]

Relevant warning:

[2020-09-17 00:01:43] [WARNING] discord.gateway: Shard ID 0 heartbeat blocked for more than 10 seconds.
Loop thread traceback (most recent call last):
  File "/usr/lib/python3.8/runpy.py", line 193, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/usr/lib/python3.8/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/redbot/__main__.py", line 548, in <module>
    main()
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/redbot/__main__.py", line 511, in main
    loop.run_forever()
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/discord/client.py", line 312, in _run_event
    await coro(*args, **kwargs)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/redbot/core/events.py", line 309, in on_message
    await bot.process_commands(message)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/redbot/core/bot.py", line 1066, in process_commands
    await self.invoke(ctx)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/discord/ext/commands/bot.py", line 903, in invoke
    await ctx.command.invoke(ctx)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/redbot/core/commands/commands.py", line 825, in invoke
    await super().invoke(ctx)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/discord/ext/commands/core.py", line 1307, in invoke
    await ctx.invoked_subcommand.invoke(ctx)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/discord/ext/commands/core.py", line 855, in invoke
    await injected(*ctx.args, **ctx.kwargs)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/discord/ext/commands/core.py", line 85, in wrapped
    ret = await coro(*args, **kwargs)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/redbot/cogs/downloader/downloader.py", line 812, in _cog_unin>
    ctx.bot.unload_extension(real_name)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/discord/ext/commands/bot.py", line 694, in unload_extension
    self._remove_module_references(lib.__name__)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/discord/ext/commands/bot.py", line 565, in _remove_module_ref>
    self.remove_cog(cogname)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/redbot/core/bot.py", line 1127, in remove_cog
    super().remove_cog(cogname)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/discord/ext/commands/bot.py", line 551, in remove_cog
    cog._eject(self)
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/discord/ext/commands/cog.py", line 424, in _eject
    self.cog_unload()
  File "/home/ubuntu/red-data/cogs/CogManager/cogs/qupyter/qupyter.py", line 56, in cog_unload
    self.stop_app()
  File "/home/ubuntu/red-data/cogs/CogManager/cogs/qupyter/qupyter.py", line 81, in stop_app
    self.app.close()
  File "/home/ubuntu/red-data/cogs/CogManager/cogs/qupyter/ipykernel_utils.py", line 290, in close
    super().close()
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/ipykernel/kernelapp.py", line 333, in close
    self.context.term()
  File "/home/ubuntu/red-venv/lib/python3.8/site-packages/zmq/sugar/context.py", line 154, in term
    return super(Context, self).term()