code: public ByteBuffer getSecretStage(final String secretId, final Stage stage) {
          final GetSecretValueRequest getSecretValueRequest = new GetSecretValueRequest();
          getSecretValueRequest.setSecretId(secretId);
          getSecretValueRequest.setVersionStage(stage.getAwsName());
          final GetSecretValueResult result = getDelegate().getSecretValue(getSecretValueRequest);
          return result.getSecretBinary();
      }
docs: Retrieve a specific stage of the secret.
  
  @param secretId the ARN of the secret
  @param stage the stage of the secret to retrieve
  @return the Fernet key or keys in binary form