@Override
    public void enableConnHeartbeat(Url url) {
        ensureStarted();
        if (null != url) {
            this.connectionManager.enableHeartbeat(this.connectionManager.get(url.getUniqueKey()));
        }
    }
Close all connections of a address

@param addr address
src/main/java/com/alipay/remoting/rpc/RpcClient.java