in src/main/java/com/microsoft/azure/proton/transport/proxy/impl/ProxyAuthenticator.java [122:127]
private static boolean isProxyAddressLegal(final List<Proxy> proxies) {
return proxies != null
&& !proxies.isEmpty()
&& proxies.get(0).address() != null
&& proxies.get(0).address() instanceof InetSocketAddress;
}