I couldn't find any official documentation specifying what each parameter to a `sla_miss_callback` callable are. This would be a great addition to know how to properly format the messages sent.
airflow/models/dag.py
self,
        state: DagRunState,
        execution_date: Optional[datetime] = None,
        run_id: Optional[str] = None,
        start_date: Optional[datetime] = None,
        external_trigger: Optional[bool] = False,
        conf: Optional[dict] = None,
        run_type: Optional[DagRunType] = None,
        session=None,
        dag_hash: Optional[str] = None,
        creating_job_id: Optional[int] = None,
        data_interval: Optional[Tuple[datetime, datetime]] = None,
    ):
        """
        Creates a dag run from this dag including the tasks associated with this dag.
        Returns the dag run.
        :param run_id: defines the run id for this dag run
        :type run_id: str
        :param run_type: type of DagRun
        :type run_type: airflow.utils.types.DagRunType
        :param execution_date: the execution date of this dag run
        :type execution_date: datetime.datetime
        :param state: the state of the dag run
        :type state: airflow.utils.state.DagRunState
        :param start_date: the date this dag run should be evaluated
        :type start_date: datetime
        :param external_trigger: whether this dag run is externally triggered
        :type external_trigger: bool
        :param conf: Dict containing configuration/parameters to pass to the DAG
        :type conf: dict