static final String PORT = System.getProperty("port", "test_port");
public static void main(String[] args) throws Exception {
// Address to bind on / connect to.
final LocalAddress addr = new LocalAddress(PORT);
EventLoopGroup serverGroup = new LocalEventLoopGroup();
EventLoopGroup clientGroup = new NioEventLoopGroup(); // NIO event loops are also OK
try {
// Note that we can use any event loop to ensure certain local channels