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。  


import org.apache.dubbo.remoting.Constants;
import org.apache.dubbo.remoting.RemotingException;
import org.apache.dubbo.remoting.api.WireProtocol;
import org.apache.dubbo.remoting.api.pu.AbstractPortUnificationServer;
import org.apache.dubbo.remoting.transport.dispatcher.ChannelHandlers;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.PooledByteBufAllocator;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.util.concurrent.Future;
import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static org.apache.dubbo.common.constants.CommonConstants.ANYHOST_KEY;
import static org.apache.dubbo.common.constants.CommonConstants.ANYHOST_VALUE;
import static org.apache.dubbo.common.constants.CommonConstants.IO_THREADS_KEY;
import static org.apache.dubbo.common.constants.LoggerCodeConstants.TRANSPORT_FAILED_CLOSE;
import static org.apache.dubbo.remoting.Constants.EVENT_LOOP_BOSS_POOL_NAME;
import static org.apache.dubbo.remoting.Constants.EVENT_LOOP_WORKER_POOL_NAME;
/**
 * PortUnificationServer.
 */
public class NettyPortUnificationServer extends AbstractPortUnificationServer {