https://github.com/apache/airflow/blob/main/airflow/dag_processing/manager.py#L773
"""Information about single processing of one file."""
    num_dags: int
    import_errors: int
    last_finish_time: datetime | None
    last_duration: timedelta | None
    run_count: int
class DagParsingSignal(enum.Enum):
    """All signals sent to parser."""
    AGENT_RUN_ONCE = "agent_run_once"
    TERMINATE_MANAGER = "terminate_manager"
    END_MANAGER = "end_manager"
class DagFileProcessorAgent(LoggingMixin, MultiprocessingStartMethodMixin):
    """
    Agent for DAG file processing.
    It is responsible for all DAG parsing related jobs in scheduler process.
    Mainly it can spin up DagFileProcessorManager in a subprocess,
    collect DAG parsing results from it and communicate signal/DAG parsing stat with it.
    This class runs in the main `airflow scheduler` process.
    :param dag_directory: Directory where DAG definitions are kept. All
        files in file_paths should be under this directory
    :param max_runs: The number of times to parse and schedule each file. -1
        for unlimited.
    :param processor_timeout: How long to wait before timing out a DAG file processor
    :param dag_ids: if specified, only schedule tasks with these DAG IDs
    :param pickle_dags: whether to pickle DAGs.
    :param async_mode: Whether to start agent in async mode
    """
    def __init__(