docs: public static String signUsingRsaSha256(
        PrivateKey privateKey,
        JsonFactory jsonFactory,
        JsonWebSignature.Header header,
        JsonWebToken.Payload payload)
        throws GeneralSecurityException, IOException {
      String content =
          Base64.encodeBase64URLSafeString(jsonFactory.toByteArray(header))
              + "."
              + Base64.encodeBase64URLSafeString(jsonFactory.toByteArray(payload));
      byte[] contentBytes = StringUtils.getBytesUtf8(content);
      byte[] signature =
          SecurityUtils.sign(
              SecurityUtils.getSha256WithRsaSignatureAlgorithm(), privateKey, contentBytes);
      return content + "." + Base64.encodeBase64URLSafeString(signature);
    }