static String pem(Certificate cert) throws IOException {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        try (PemWriter pemWriter = new PemWriter(new OutputStreamWriter(out, StandardCharsets.UTF_8))) {
            pemWriter.writeObject(new JcaMiscPEMGenerator(cert));
        }
        return new String(out.toByteArray(), StandardCharsets.UTF_8);
    }
Creates a keystore with a single key and saves it to a file.

@param filename String file to save
@param password String store password to set on keystore
@param keyPassword String key password to set on key
@param alias String alias to use for the key
@param privateKey Key to save in keystore
@param cert Certificate to use as certificate chain associated to key
@throws GeneralSecurityException for any error with the security APIs
@throws IOException if there is an I/O error saving the file
clients/src/test/java/org/apache/kafka/test/TestSslUtils.java