Netty UDP 使用采坑

EventLoopGroup workerGroup = new NioEventLoopGroup(20);
        try {
            Bootstrap b = new Bootstrap();
            b.group(workerGroup);
            b.channel(NioDatagramChannel.class);
            b.option(ChannelOption.SO_BROADCAST, true);
            b.option(ChannelOption.SO_RCVBUF, 2048 * 2048);
            b.handler(udpInboundHandler);
            ChannelFuture f = b.bind(port).sync();
            f.channel().closeFuture().sync();
        } finally {
            workerGroup.shutdownGracefully();
        }