@Override
    public void setName(final String name) {
        super.setName(name);
        // topic == name by default
        if (this.topic == null) {
            this.setTopic(this.topic);
        }
    }
Set the name of this Appender.
metamorphosis-client-extension/src/main/java/com/taobao/metamorphosis/client/extension/log4j/StreamAppender.java