* Implement time triggers with offset for timestamp sensors
* Fix bad change
* Add testcase for multiple conf_at with offsets
* Fix fixture rename
* Fix testcase - if no offset provided, it should be just the string of the entity id
* Get test to pass
* Simplify code
* Update the messaging and make the offset optional allowing specifying only the entity_id
* Move state tracking one level up
* Implement requesteed changes
* Significantly speed up single entity/response service calls
Since the majority of service calls are single entity, we can
avoid creating tasks in this case. Since the multi-entity
service calls always check the result and raise, we can switch
the asyncio.wait to asyncio.gather
* Significantly speed up single entity/response service calls
Since the majority of service calls are single entity, we can
avoid creating tasks in this case. Since the multi-entity
service calls always check the result and raise, we can switch
the asyncio.wait to asyncio.gather
* revert
* cannot be inside pytest.raises
* one more
* Update homeassistant/helpers/service.py
