* Remove async_remove_listener
This avoids the ambuigity as to what happens if same callback is added multiple times.
* Keep track of a context for each listener
This allow a update coordinator to adapt what data to request on update from the backing service based on which entities are enabled.
* Clone list before calling callbacks
The callbacks can end up unregistering and modifying the dict while iterating.
* Only yield actual values
* Add a test for update context
* Factor out iteration of _listeners to helper
* Verify context is passed to coordinator
* Switch to Any as type instead of object
* Remove function which use was dropped earliers
The use was removed in 8bee25c938
