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(
        NettyPortUnificationServerHandler.class);
    private final URL url;
    private final ChannelHandler handler;
    private final boolean detectSsl;
    private final List<WireProtocol> protocols;
    private final Map<String, Channel> dubboChannels;
    private final Map<String, URL> urlMapper;
    private final Map<String, ChannelHandler> handlerMapper;
    public NettyPortUnificationServerHandler(URL url, boolean detectSsl,
                                             List<WireProtocol> protocols, ChannelHandler handler,
                                             Map<String, Channel> dubboChannels, Map<String, URL> urlMapper, Map<String, ChannelHandler> handlerMapper) {
        this.url = url;
        this.protocols = protocols;
        this.detectSsl = detectSsl;
        this.handler = handler;
        this.dubboChannels = dubboChannels;
        this.urlMapper = urlMapper;
        this.handlerMapper = handlerMapper;
    }
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        LOGGER.error(INTERNAL_ERROR, "unknown error in remoting module", "", "Unexpected exception from downstream before protocol detected.", cause);
    }
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {