Enumerates the possible states that the batch request can be
in.
Values:
STATE_UNSPECIFIED (0):
Invalid.
PROCESSING (1):
Request is actively being processed.
SUCCESSFUL (2):
The request is done and at least one item has
been successfully processed.
FAILED (3):
The request is done and no item has been
successfully processed.
CANCELLED (4):
The request is done after the
longrunning.Operations.CancelOperation has been
called by the user. Any records that were
processed before the cancel command are output
as specified in the request.