Optional[customOptional[unknownOptionalendIteration end time.
OptionalerrorHuman-readable error description. Populated only if state is FAILED.
Number of objects transferred during this iteration.
Total size of objects transferred during this iteration.
Sequence number of the iteration in the transfer, starting from 1.
OptionalstartIteration start time.
Current iteration state.
Average throughput in bytes per second during the iteration.