static String[] maybeAddTls13(boolean enableTls13, String... defaultProtocols) {
        if (enableTls13) {
            String[] protocols = new String[defaultProtocols.length + 1];
            System.arraycopy(defaultProtocols, 0, protocols, 1, defaultProtocols.length);
            protocols[0] = "TLSv1.3";
            return protocols;
        } else {
            return defaultProtocols;
        }
    }
Client Ssl Context Factory

Author: Arthur Gonigberg
Date: May 14, 2018
zuul-core/src/main/java/com/netflix/zuul/netty/ssl/ClientSslContextFactory.java