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