So, the major state of the bucket is described as
complete (and vs.
delegated in some cases).
Minor bucket state (bucket progress)
Sometimes we want to be able to track the progress in more details to avoid needless re-processing objects from the start of the bucket. It might be even unavoidable for tasks that have no bucket creation specification i.e. that end up with a single work bucket (in such tasks we do not want to distribute the work, just to implement stateful suspend+resume).