// Configure the client.
EventLoopGroup group = new NioEventLoopGroup();
try {
    Bootstrap b = new Bootstrap();
    b.group(group)
        .channel(NioSocketChannel.class)
        .option(ChannelOption.TCP_NODELAY, true)
        .handler(new ChannelInitializer<SocketChannel>() {
            @Override
            public void initChannel(SocketChannel ch) throws Exception {
                ChannelPipeline p = ch.pipeline();
                if (sslCtx != null) {
                    p.addLast(sslCtx.newHandler(ch.alloc(), HOST, PORT));
                }
                //p.addLast(new LoggingHandler(LogLevel.INFO));
                p.addLast(new EchoClientHandler());
            }
        });

    // Start the client.
    ChannelFuture f = b.connect(HOST, PORT).sync();

    // Wait until the connection is closed.
    f.channel().closeFuture().sync();