code: public static GoogleCloudStorageItemInfo createItemInfoForBucket(
        StorageResourceId resourceId, Bucket bucket) {
      Preconditions.checkArgument(resourceId != null, "resourceId must not be null");
      Preconditions.checkArgument(bucket != null, "bucket must not be null");
      Preconditions.checkArgument(
          resourceId.isBucket(), "resourceId must be a Bucket. resourceId: %s", resourceId);
      Preconditions.checkArgument(
          resourceId.getBucketName().equals(bucket.getName()),
          "resourceId.getBucketName() must equal bucket.getName(): '%s' vs '%s'",
          resourceId.getBucketName(), bucket.getName());
  
      // For buckets, size is 0.
      return new GoogleCloudStorageItemInfo(resourceId, bucket.getTimeCreated().getValue(),
          0, bucket.getLocation(), bucket.getStorageClass());
    }
docs: Helper for converting a StorageResourceId + Bucket into a GoogleCloudStorageItemInfo.