dubbo2.7.x升级到3.2.x后 应用跑两三天后就发生内存泄漏。

在 org.apache.dubbo.remoting.transport.netty4.NettyChannel的劝酒的私有的静态成员变量CHANNEL_MAP里的。
里面55多万个元素，1.1G的大小。 

到后面AbstractInvoker.waitForResultIfSync(底层是threadlessExecutor.waitAndDrain)会卡住，比如： 某个服务正常调用不到100ms就返回了，应用跑两三天后就开始 那个正常的服务调用开始20%的概率出现一次两三秒的卡顿。  


private static final ErrorTypeAwareLogger logger = LoggerFactory.getErrorTypeAwareLogger(NettyPortUnificationServer.class);
    private final int serverShutdownTimeoutMills;
    /**
     * netty server bootstrap.
     */
    private ServerBootstrap bootstrap;
    /**
     * the boss channel that receive connections and dispatch these to worker channel.
     */
    private io.netty.channel.Channel channel;
    private EventLoopGroup bossGroup;
    private EventLoopGroup workerGroup;
    private final Map<String, Channel> dubboChannels = new ConcurrentHashMap<>();
    public NettyPortUnificationServer(URL url, ChannelHandler handler) throws RemotingException {
        super(url, ChannelHandlers.wrap(handler, url));
        
        
        
        serverShutdownTimeoutMills = ConfigurationUtils.getServerShutdownTimeout(
            getUrl().getOrDefaultModuleModel());