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。  


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package org.apache.dubbo.remoting.transport.netty4;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.config.ConfigurationUtils;
import org.apache.dubbo.common.logger.ErrorTypeAwareLogger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.apache.dubbo.common.utils.CollectionUtils;
import org.apache.dubbo.common.utils.NetUtils;
import org.apache.dubbo.remoting.Channel;
import org.apache.dubbo.remoting.ChannelHandler;