The number of times to retry the modification if the bucket's metageneration changes
in the read/modify/write cycle. If this property is not set, a suitable default is used.
The value must not be negative.
Modifying bucket labels involves reading the bucket metadata in one request,
then sending another request with the new labels, including a metageneration check
to ensure that the bucket hasn't changed between the two requests. If the metageneration
has changed, the overall operation can be retried from the start. This property indicates
the number of retries, so it has a minimum value of 0.