static SSLEngine getDelegate(SSLEngine engine) {
        if (engine instanceof Java8EngineWrapper) {
            return ((Java8EngineWrapper) engine).delegate;
        }
        return engine;
    }
A wrapper around {@link ConscryptEngine} that adapts to the new Java 9 (and potentially later
patches of 8) {@code setHandshakeApplicationProtocolSelector} API (which requires Java 8 for
compilation, due to the use of {@link BiFunction}).
common/src/main/java/org/conscrypt/Java8EngineWrapper.java