add property_action?

[hidaris]

In some scenarios, such as switching lights on and off, we need to do something extra to synchronize the state with the device after updating the properties, but webthing-python doesn't seem to implement this feature, I add this in aiowebthing, property:

async def property_action(self, property_):
 """
 Additional action when a property change.
 property_ -- the property that changed
 """
 pass

usage example:

class Z2mThing(Thing):
 async def property_action(self, property_):
 if property_.name == "state":
 value = "ON" if await property_.get_value() else "OFF"
 else:
 value = await property_.get_value()
 await mqtt.publish(f"zigbee2mqtt/{self.id}/set", {property_.name: value})

[mrstegeman]

Couldn't this all be done as part of the value_forwarder callback in the Value class?