code: public Acl getBlobAcl(String bucketName, String blobName, long blobGeneration) {
      // [START getBlobAcl]
      BlobId blobId = BlobId.of(bucketName, blobName, blobGeneration);
      Acl acl = storage.getAcl(blobId, User.ofAllAuthenticatedUsers());
      // [END getBlobAcl]
      return acl;
    }
docs: [VARIABLE 42]