Detail payload fired with a data-change event. Fires whenever the
machine's data payload is replaced. old_data is the value before the
change; new_data is the value after. cause names the API family that
performed the replacement: a data-bearing transition, an override, or
a direct set_data call.
Detail payload fired with a
data-changeevent. Fires whenever the machine's data payload is replaced.old_datais the value before the change;new_datais the value after.causenames the API family that performed the replacement: a data-bearingtransition, anoverride, or a directset_datacall.