private static void safeDelete(File certFile) {
        if (!certFile.delete()) {
            if (logger.isWarnEnabled()) {
                logger.warn("Failed to delete a file: " + certFile);
            }
        }
    }
Deletes the generated X.509 certificate file and RSA private key file.
core/src/main/java/com/linecorp/armeria/internal/common/util/SelfSignedCertificate.java