Response message for the ImportProductSets method.
This message is returned by the
google.longrunning.Operations.GetOperation][google.longrunning.Operations.GetOperation]
method in the returned
google.longrunning.Operation.response][google.longrunning.Operation.response]
field.
The rpc status for each ImportProductSet request, including
both successes and errors. The number of statuses here
matches the number of lines in the csv file, and statuses[i]
stores the success or failure status of processing the i-th
line of the csv, starting from line 0.