@Override
    public Optional<String> extract(final Authentication authentication,
                                    final HttpServletRequest request,
                                    final HttpServletResponse response) {
        return Optional.ofNullable(ClientInfoHolder.getClientInfo().getDeviceFingerprint());
    }
Extracts the browser fingerprint from the request
as collected during authentication attempts from the client.

@author Misagh Moayyed
@since 7.1.0
support/cas-server-support-trusted-mfa-core/src/main/java/org/apereo/cas/trusted/web/flow/fingerprint/BrowserDeviceFingerprintExtractor.java