Emit an event (not an RPC return) to the parent thread.
Parameters
payload: any
Arbitrary JSON-cloneable data; shallow-cloned with lodash/cloneDeep before postMessage.
Common shape: { id, event, data } where event selects a handler on UdsTester.eventHandlerMap.
Returns void
Remarks
No promise is returned — the parent must acknowledge async work through a follow-up RPC such as __eventDone
when the payload includes a correlation id managed by emitMap.
Emit an event (not an RPC return) to the parent thread.