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
return self._default_view
    @property
    def pickle_id(self) -> Optional[int]:
        return self._pickle_id
    @pickle_id.setter
    def pickle_id(self, value: int) -> None:
        self._pickle_id = value
    def param(self, name: str, default=None) -> DagParam:
        """
        Return a DagParam object for current dag.
        :param name: dag parameter name.
        :param default: fallback value for dag parameter.
        :return: DagParam instance for specified name and current dag.
        """
        return DagParam(current_dag=self, name=name, default=default)
    @property
    def tasks(self) -> List[BaseOperator]:
        return list(self.task_dict.values())
    @tasks.setter
    def tasks(self, val):
        raise AttributeError('DAG.tasks can not be modified. Use dag.add_task() instead.')
    @property
    def task_ids(self) -> List[str]:
        return list(self.task_dict.keys())
    @property
    def task_group(self) -> "TaskGroup":
        return self._task_group
    @property
    def filepath(self) -> str: