Depends on what the invokers wants. If the invoker only wants to log things to disk and read those logs later, surely he can do it himself. What XLog provides for the invoker under the hood is essentially performance: the invoker can log lots of things and does not need to worry about IO speed, disk space, and log safety. And of course it's cross platform. A detailed performance analysis is here (in Mandarin Chinese): http://mp.weixin.qq.com/s/cnhuEodJGIbdodh0IxNeXQ