Metadata used for long running operations returned by CTS
batch APIs. It's used to replace
google.longrunning.Operation.metadata][google.longrunning.Operation.metadata].
More detailed information about operation state.
Count of failed item(s) inside an operation.
The time when the batch operation is created.
The time when the batch operation is finished and [google.long
running.Operation.done][google.longrunning.Operation.done] is
set to true.