https://github.com/apache/airflow/blob/main/airflow/dag_processing/manager.py#L773
self.print_stats_interval = conf.getint("scheduler", "print_stats_interval")
        
        self._processors: dict[str, DagFileProcessorProcess] = {}
        self._num_run = 0
        
        self._file_stats: dict[str, DagFileStat] = {}
        
        self.last_dag_dir_refresh_time = timezone.make_aware(datetime.fromtimestamp(0))
        
        self.last_stat_print_time = 0
        
        self.last_deactivate_stale_dags_time = timezone.make_aware(datetime.fromtimestamp(0))
        
        self.parsing_cleanup_interval = conf.getint("scheduler", "parsing_cleanup_interval")
        
        self._processor_timeout = processor_timeout
        
        self.dag_dir_list_interval = conf.getint("scheduler", "dag_dir_list_interval")
        
        self._callback_to_execute: dict[str, list[CallbackRequest]] = defaultdict(list)
        self._log = logging.getLogger("airflow.processor_manager")
        self.waitables: dict[Any, MultiprocessingConnection | DagFileProcessorProcess] = (
            {
                self._direct_scheduler_conn: self._direct_scheduler_conn,
            }
            if self._direct_scheduler_conn is not None
            else {}
        )
    def register_exit_signals(self):