outcome

The outcome of this artifact transform execution: * failed - Artifact transform execution which failed * success - Artifact transform execution which was successfully executed * from_cache - Artifact transform execution which was taken from cache * up_to_date - Artifact transform execution which was up-to-date * unknown - Artifact transform execution whose outcome is unknown * skipped - Artifact transform execution which was skipped. This is not emitted anymore, replaced by up_to_date.