### 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
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"""
DebugExecutor.
.. seealso::
    For more information on how the DebugExecutor works, take a look at the guide:
    :ref:`executor:DebugExecutor`
"""
from __future__ import annotations
import threading
from typing import Any
from airflow.configuration import conf
from airflow.executors.base_executor import BaseExecutor
from airflow.models.taskinstance import TaskInstance, TaskInstanceKey
from airflow.utils.state import State
class DebugExecutor(BaseExecutor):
    """
    This executor is meant for debugging purposes. It can be used with SQLite.
    It executes one task instance at time. Additionally to support working
    with sensors, all sensors ``mode`` will be automatically set to "reschedule".
    """
    _terminated = threading.Event()
    def __init__(self):
        super().__init__()
        self.tasks_to_run: list[TaskInstance] = []
        
        self.tasks_params: dict[TaskInstanceKey, dict[str, Any]] = {}
        self.fail_fast = conf.getboolean("debug", "fail_fast")
    def execute_async(self, *args, **kwargs) -> None: