asyncio.py 文件源码

def start(self):
        old_current = IOLoop.current(instance=False)
        try:
            self._setup_logging()
            self.make_current()
            self.asyncio_loop.run_forever()
        finally:
            if old_current is None:
                IOLoop.clear_current()
            else:
                old_current.make_current()