code: public byte[] readEncryptedBlob(String bucketName, String blobName, String decryptionKey) {
      // [START readEncryptedBlob]
      byte[] content =
          storage.readAllBytes(bucketName, blobName, BlobSourceOption.decryptionKey(decryptionKey));
      // [END readEncryptedBlob]
      return content;
    }
docs: [VARIABLE "my_encryption_key"]