exception netty ReferenceCountUtil safeRelease

Question

public class EchoServer {

private final int port;

public EchoServer(int port) {
    this.port = port;
}


public static void main(String[] args) throws InterruptedException {
    new EchoServer(80).start();
}

public void start() throws InterruptedException {
    EchoServerHandler handler = new EchoServerHandler();
    MyHandler myHandler = new MyHandler();
    EventLoopGroup group = new NioEventLoopGroup();

    try {
        ServerBootstrap b = new ServerBootstrap();
        b.group(group)
                .channel(NioServerSocketChannel.class)
                .localAddress(new InetSocketAddress(port))
                .childHandler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    public void initChannel(SocketChannel ch) throws Exception {
                        ch.pipeline().addLast(handler).addLast(myHandler);
                    }
                });

        ChannelFuture f = b.bind().sync();
        f.channel().closeFuture().sync();

    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        group.shutdownGracefully().sync();
    }
}

}

@ChannelHandler.Sharable

public class MyHandler扩展了SimpleChannelInboundHandler {

@Override
protected void channelRead0(ChannelHandlerContext ctx, ByteBuf msg)
        throws Exception {
    System.out.println(msg.refCnt());
}

}

这是我的代码，当服务器启动时，cmd-＆gt; telnet localhost 80 程序异常 服务器收到：h 1 三月08,20188 10:34:04下午io.netty.util.ReferenceCountUtil safeRelease 警告：无法发布消息：PooledUnsafeDirectByteBuf（已释放） io.netty.util.IllegalReferenceCountException：refCnt：0，increment：1     at io.netty.buffer.AbstractReferenceCountedByteBuf.release0（AbstractReferenceCountedByteBuf.java:100）     在io.netty.buffer.AbstractReferenceCountedByteBuf.release（AbstractReferenceCountedByteBuf.java:84）

我不知道为什么