private static String getUniquifierPrefix() {
        // To make a request ID globally unique, we will add MAC-based machine ID and a random number.
        // The random number tries to make this instance unique in the same machine and process.
        try (TemporaryThreadLocals tempThreadLocals = TemporaryThreadLocals.acquire()) {
            final byte[] r = tempThreadLocals.byteArray(6);
            ThreadLocalRandom.current().nextBytes(r);
            final Encoder encoder = Base64.getEncoder();
            return new StringBuilder().append(encoder.encodeToString(defaultMachineId()))
                                      .append(encoder.encodeToString(r))
                                      .toString();
        }
    }
A {@link SamlRequestIdManager} implementation based on JSON Web Tokens specification.

@see <a href="https://jwt.io/">JSON Web Tokens</a>
saml/src/main/java/com/linecorp/armeria/server/saml/JwtBasedSamlRequestIdManager.java