Advance one or every queued/running job by one step.
OptionaljobId: stringOnly this job; omit for all.
Whether any job advanced.
Fail a job, pushing hashtree.error.
Job to fail.
Optionalerror: stringError code. Default store-failed.
Whether the job existed and was still in progress.
Script the next pickFiles outcome.
A file set, or 'cancel' for file-pick-cancelled.
The hashtree mock with job and picker controls.