Returns a step's start payload: the stored PayloadAtStart when present, otherwise the PayloadAtEnd of the step that PayloadAtStartSourceStepID points at, otherwise null. Pure; accepts entity objects or plain rows.
PayloadAtStart
PayloadAtEnd
PayloadAtStartSourceStepID
The step whose start payload to resolve.
Steps of the same run, keyed by ID (see IndexByUUID).
IndexByUUID
The start payload JSON, or null when the step has none or its source step is not in the map.
Returns a step's start payload: the stored
PayloadAtStartwhen present, otherwise thePayloadAtEndof the step thatPayloadAtStartSourceStepIDpoints at, otherwise null. Pure; accepts entity objects or plain rows.