I continue research slixmpp and right now I receive race condition state in multithread environment.

I create synthetic code bases on my simplify project code:

class Worker()

    async def process(...):
        c = Client(...) # NOTE - here you may provide loop parameter to simplify set loop
        await c.connect(...)

    def run()
        #
        loop = new_event_loop()
        set_event_loop(loop)     # HACK - to get_event_loop does not raise error in ClientXMPP
        #
        loop.create_task(self.process())
        loop.run_forever()

class App()
    def run()
        for w in range(5):
            w = Worker()
            w.start()

And I receive PluginNotFount on slixmpp.plugins.base in line 157.