HtmlWebpackPlugin源码中的Events执行分析？

Question

To allow other plugins to alter the html this plugin executes the following events:
Async:
html-webpack-plugin-before-html-generation
html-webpack-plugin-before-html-processing
html-webpack-plugin-alter-asset-tags
html-webpack-plugin-after-html-processing
html-webpack-plugin-after-emit
Sync:
html-webpack-plugin-alter-chunks

这些事件是何时如何被运行的？大神指条明路呗？

Answer 1

自己看了半天源码，知道了：
关键点：发布订阅模式；
关键文件：Tapable.js；
关键方法：Tapable.prototype.plugin,Tapable.prototype.applyPluginsWaterfall,Tapable.prototype.applyPluginsAsyncWaterfall