public interface B2BucketTypes
B2BucketTypes provides constants for well-known bucket types.
DESIGN NOTE: It is *not* an enum because new bucket types will be added
over time and we want code to be able to get a bucket from
the service, change an attribute, and use it in an update
operation. If we used an enum, even with the
BzJson.defaultForInvalidEnumValue() annotation, we wouldn't
be able to operate generically on buckets with unknown
bucketTypes. (hmmmm...b2_update_bucket could treat bucketType
'unknown' as a way of saying "don't change".)