code: public Acl getDefaultBucketAcl(String bucketName) {
      // [START getDefaultBucketAcl]
      Acl acl = storage.getDefaultAcl(bucketName, User.ofAllAuthenticatedUsers());
      // [END getDefaultBucketAcl]
      return acl;
    }
docs: [VARIABLE "my_unique_bucket"]