### Overview
Some Executors, currently a subset of the local Executors, run in a single threaded fashion and have certain limitations and requirements, many of which are hardcoded. To add a new single threaded Executor would require changes to core Airflow code.
Note: This coupling often shows up with SQLite compatibility checks since it does not support multiple connections.
### Examples
- **2a**) SQLite check done in configuration.py: https://github.com/apache/airflow/blob/26f94c5370587f73ebd935cecf208c6a36bdf9b6/airflow/configuration.py#L412-L419
- **2b**) When running in standalone mode SQLite compatibility is checked: https://github.com/apache/airflow/blob/26f94c5370587f73ebd935cecf208c6a36bdf9b6/airflow/cli/commands/standalone_command.py#L160-L165
- **2c**) Sensors in `poke` mode can block execution of DAGs when running with single process Executors, currently hardcoded to DebugExecutor (although should also include SequentialExecutor): https://github.com/apache/airflow/blob/27e2101f6ee5567b2843cbccf1dca0b0e7c96186/airflow/sensors/base.py#L243
### Proposal
A static method or attribute on the Executor class which can be checked by core code.

There is a precedent already set with the `supports_ad_hoc_ti_run` attribute, see:
https://github.com/apache/airflow/blob/fb741fd87254e235f99d7d67e558dafad601f253/airflow/executors/kubernetes_executor.py#L435 https://github.com/apache/airflow/blob/26f94c5370587f73ebd935cecf208c6a36bdf9b6/airflow/www/views.py#L1735-L1737
"""Expose job ID for SchedulerJob."""
        self._job_id = value
        self.kubernetes_executor.job_id = value
        self.celery_executor.job_id = value
    def start(self) -> None:
        """Start celery and kubernetes executor."""
        self.celery_executor.start()
        self.kubernetes_executor.start()
    @property
    def slots_available(self) -> int:
        """Number of new tasks this executor instance can accept."""
        return self.celery_executor.slots_available
    def queue_command(
        self,
        task_instance: TaskInstance,
        command: CommandType,
        priority: int = 1,
        queue: str | None = None,
    ) -> None:
        """Queues command via celery or kubernetes executor."""
        executor = self._router(task_instance)
        self.log.debug("Using executor: %s for %s", executor.__class__.__name__, task_instance.key)
        executor.queue_command(task_instance, command, priority, queue)
    def queue_task_instance(