org.apache.dubbo.remoting.exchange.support.DefaultFuture#closeChannel doesn't work as expected since the channel instances to be compared do not have correct equals() implementation:

```java
 public static void closeChannel(Channel channel) {
        for (Map.Entry<Long, Channel> entry : CHANNELS.entrySet()) {
            if (channel.equals(entry.getValue())) { // in netty4, channel is NettyChannel, but entry.getValue() is NettyClient, equals will return false.
                DefaultFuture future = getFuture(entry.getKey());
                if (future != null && !future.isDone()) {
                    Response disconnectResponse = new Response(future.getId());
                    disconnectResponse.setStatus(Response.CHANNEL_INACTIVE);
                    disconnectResponse.setErrorMessage("Channel " +
                            channel +
                            " is inactive. Directly return the unFinished request : " +
                            future.getRequest());
                    DefaultFuture.received(channel, disconnectResponse);
                }
            }
        }
    }
```

This is the root cause of issue 1 in  #1968.
}
        } catch (Throwable e) {
            throw new RemotingException(this, "Failed to send message " + message + " to " + getRemoteAddress() + ", cause: " + e.getMessage(), e);
        }
        if (!success) {
            throw new RemotingException(this, "Failed to send message " + message + " to " + getRemoteAddress()
                    + "in timeout(" + timeout + "ms) limit");
        }
    }
    @Override
    public void close() {
        try {
            super.close();
        } catch (Exception e) {
            logger.warn(e.getMessage(), e);
        }
        try {
            removeChannelIfDisconnected(channel);
        } catch (Exception e) {
            logger.warn(e.getMessage(), e);
        }
        try {
            attributes.clear();
        } catch (Exception e) {
            logger.warn(e.getMessage(), e);
        }
        try {
            if (logger.isInfoEnabled()) {
                logger.info("Close netty channel " + channel);
            }