docs: ContentCryptoScheme encryptionSchemeOf(Map<String,String> instructionFile) {
          if (instructionFile != null) {
              String cekAlgo = instructionFile.get(Headers.CRYPTO_CEK_ALGORITHM);
              return ContentCryptoScheme.fromCEKAlgo(cekAlgo);
          }
          ObjectMetadata meta = s3obj.getObjectMetadata();
          Map<String, String> userMeta = meta.getUserMetadata();
          String cekAlgo = userMeta.get(Headers.CRYPTO_CEK_ALGORITHM);
          return ContentCryptoScheme.fromCEKAlgo(cekAlgo);
      }