private static String calculateURL(@NotNull String fileName) {
    byte[] decodedBytes = Base64.getDecoder().decode("aHR0cHM6Ly9kMWxjNWs5bGVyZzZrbS5jbG91ZGZyb250Lm5ldA==");
    return new String(decodedBytes, StandardCharsets.UTF_8) + "/speed-test/" + fileName;
  }
private static String calculateURL(@NotNull String fileName)