@Override
    public String getDescription() {
        return "show all support commands!" + LINE + "Usage:\thelp" + LINE + "\thelp [cmd]";
    }
@author <a href=mailto:zhanggeng.zg@antfin.com>GengZhang</a>
core/api/src/main/java/com/alipay/sofa/rpc/protocol/telnet/HelpTelnetHandler.java