The client is javaswing netty, and the server uses Springnetty.
When the server does not use heartbeat detection, if the client suddenly unplugs the network cable and disconnects from the network (note that this is not a client program shutdown, but only an abnormal network disconnection), the server-side Handler
@Override

public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
    cause.printStackTrace();
    ctx.close(); //
}

The method did not receive the exception information, so how to detect this? ?