docs: public static String getChunkSeedSignature(Request request, String region, String secretKey)
      throws NoSuchAlgorithmException, InvalidKeyException {
      String contentSha256 = request.header("x-amz-content-sha256");
      DateTime date = DateFormat.AMZ_DATE_FORMAT.parseDateTime(request.header("x-amz-date"));
  
      Signer signer = new Signer(request, contentSha256, date, region, null, secretKey, null);
      signer.setScope();
      signer.setCanonicalRequest();
      signer.setStringToSign();
      signer.setSigningKey();
      signer.setSignature();
      
      return signer.signature;
    }