使用run_in_executor时未捕获TimeoutError问题求助

我开发了一个程序，负责处理设备传来的数据流并写入WebSocket供Web应用消费。读取设备并通过yield输出计算值的库是同步阻塞的，不想重写为异步，所以用asyncio的run_in_executor放到线程里跑（框架用的是Tornado来支持Web请求）。

代码能正常运行，但频繁弹出「Future exception was never retrieved」错误，根源是执行器里运行的阻塞函数触发了TimeoutError。

注意：如果不把asyncio事件策略设为tornado.platform.asyncio.AnyThreadEventLoopPolicy()，执行器里的函数根本跑不起来，会一直报「there is no current event loop in ThreadExecutor」，目前没找到其他解决办法。

class ClientHandler(tornado.websocket.WebSocketHandler):
    clients = set()

    def __init__(self, *args, **kwargs):
        self.config = kwargs.pop("config")
        super().__init__(*args, **kwargs)
        self.started = False

    def on_message(self, message):
        if message == "data":
            WebClientStreamHandler.clients.add(self)

            self.start_client()

    def write_data(self, message: str):
        for client in WebClientStreamHandler.clients:
            client.write_message(message)


    def start_client(self):
        if self.started:
            return
        
        asyncio.set_event_loop_policy(tornado.platform.asyncio.AnyThreadEventLoopPolicy())
        sync_func = partial(run_client_forever, self.config)
        loop = tornado.ioloop.IOLoop.current()
        loop.run_in_executor(None, sync_func)
        self.started = True

错误信息（精简版） #

ERROR:asyncio:Future exception was never retrieved
future: <Future finished exception=TimeoutError('timed out') created at /usr/lib/python3.11/asyncio/base_events.py:427>
Traceback:
  ...
  File "/path/src/cps_demo/web_stream_handler.py", line 118, in start_client
    loop.run_in_executor(None, sync_func)
  File "/path/venv/lib/python3.11/site-packages/tornado/platform/asyncio.py", line 266, in run_in_executor
    return self.asyncio_loop.run_in_executor(executor, func, *args)
  File "/usr/lib/python3.11/asyncio/base_events.py", line 828, in run_in_executor
    return futures.wrap_future(
  File "/usr/lib/python3.11/asyncio/futures.py", line 417, in wrap_future
    new_future = loop.create_future()
  File "/usr/lib/python3.11/asyncio/base_events.py", line 427, in create_future
    return futures.Future(loop=self)
TimeoutError: timed out

内容的提问来源于stack exchange，提问作者bluppfisk