@Override
    protected void clientShutdown() {

        this.eventLoopGroup.shutdownGracefully();

        if (this.defaultEventExecutorGroup != null) {
            this.defaultEventExecutorGroup.shutdownGracefully();
        }
    }
@author Robert HG (254963746@qq.com) on 11/3/15.
lts-core/src/main/java/com/github/ltsopensource/remoting/netty/NettyRemotingClient.java