public List<X509Certificate> getClientCertificateChain() {
        return Optional.ofNullable(parent.context().get(RequestUtils.JDISC_REQUEST_X509CERT))
                .map(X509Certificate[].class::cast)
                .map(Arrays::asList)
                .orElse(List.of());
    }
@return The client certificate chain in ascending order of trust. The first certificate is the one sent from the client.
        Returns an empty list if the client did not provide a certificate.
container-core/src/main/java/com/yahoo/jdisc/http/filter/DiscFilterRequest.java