Add payload to scheduleEventAsync

I would like to add possibility to schedule an event with the payload in org.flowable.engine.impl.util.EventSubscriptionUtil#scheduleEventAsync. The payload is taken into account only in the case when there is an execution specified. Payload is not applied for signal/message start events.
Payload type is an object (in fact it is Map<String, Object>). Object serialization could be done in variable instance (scope_type_ = ‘message’ scope_id_=‘job_entity_id’).
The payload will allow us to implement signal/messageEventReceivedAsync methods in the runtimeService.
What do you think about it?

Makes sense. You also added a PR for this, right? We’ll check it and continue the discussion there.