Values:
STATE_UNSPECIFIED (0):
State not set.
CREATING (1):
Backup is being created.
FINALIZING (2):
Backup has been taken and the operation is
being finalized. At this point, changes to the
file share will not be reflected in the backup.
READY (3):
Backup is available for use.
DELETING (4):
Backup is being deleted.
INVALID (5):
Backup is not valid and cannot be used for
creating new instances or restoring existing
instances.