The SCXML System Variables _event was only minimally implemented so far.
The _event.sendid, _event.origin, _event.origintype, _event.invokeid all need to be set and handled accordingly to the external communication requirements, including their proper error handling and feedback/return values from an invoked process.
The SCXML Event I/O Processors implementation and handling was also not complete yet.
Besides completing the handling of the #_internal, #_parent and #_invokeid processors, also the 'location' field for the standard CXMLEventProcessor needs to be made available.
To support the extended _event variable handling a new EventBuilder class will be introduced, which can/should be used to build a TriggerEvent instead of instantiating these directly.
Furthermore to align with the specification naming, the TriggerEvent#payload field and getter method will be renamed to #data (getData()).
Finally, this also requires better, and fixed, handling of the management and communication (bi-directionally) with the Invoker and the statemachine invoked.
As result the AsyncTrigger class no longer is (nor can be) used and will be dropped.
Alltogether this will fix another 12+ W3C SCXML IRP tests!