Similar to renderToString, except this doesn't create extra DOM attributes such as
data-react-id, that React uses internally. This is useful if you want to use React
as a simple static page generator, as stripping away the extra attributes can save
lots of bytes.
Renders a ReactElement to its initial HTML. This should only be used on the server.
React will return an HTML string. You can use this method to generate HTML on the
server and send the markup down on the initial request for faster page loads and to
allow search engines to crawl your pages for SEO purposes.
If you call ReactDOM.render() on a node that already has this server-rendered markup,
React will preserve it and only attach event handlers, allowing you to have a very
performant first-load experience.