Loading the first file referenced by index.html takes much too long
$ npm start
> electron-performance-issue@1.0.0 start D:\electron-performance-issue
> electron .
Loading: file:///D:/electron-performance-issue/app/index.html (14 ms since last load)
Loading: file:///D:/electron-performance-issue/app/index.css (1775 ms since last load)
Loading: file:///D:/electron-performance-issue/app/index.js (0 ms since last load)