code: public Acl blobToPublicRead(String bucketName, String blobName, long blobGeneration) {
      // [START storageMakePublic]
      BlobId blobId = BlobId.of(bucketName, blobName, blobGeneration);
      Acl acl = storage.createAcl(blobId, Acl.of(User.ofAllUsers(), Role.READER));
      // [END storageMakePublic]
      return acl;
    }
docs: [VARIABLE 42]