docs: public static String getChunkSignature(String chunkSha256, DateTime date, String region, String secretKey,
                                           String prevSignature)
      throws NoSuchAlgorithmException, InvalidKeyException {
      Signer signer = new Signer(null, chunkSha256, date, region, null, secretKey, prevSignature);
      signer.setScope();
      signer.setChunkStringToSign();
      signer.setSigningKey();
      signer.setSignature();
  
      return signer.signature;
    }