Hinaloe

<blockquote>
You no longer have to use this plugin because it was merged to <a href="https://ja.wordpress.org/plugins/public-post-preview/" rel="nofollow ugc">PPP plugin</a> at v2.6.0.
</blockquote>
This plugin send <code>Cache-Control: no-cache, must-revalidate</code> header when show <a href="https://wordpress.org/plugins/public-post-preview/" rel="ugc">public-post-preview</a> post.
In other word, that make skip cache of CDN (like CloudFlare, CloudFront… and other), or Proxy-Cache (Like Nginx). 
So, outside people always can see newest draft, and there is no need extra time to close public draft.
This plugin needs PHP 5.3+
Note: If you’re using CloudFront, you should also use <a href="https://wordpress.org/plugins/c3-cloudfront-clear-cache/" rel="ugc">C3 Cloudfront Cache Controller</a>

Non Cache Public Post Preview

Disable cache when show public post preview post

kostyatereshchuk

This plugin adds a switcher button to the toolbar which allows you to switch between the recently viewed admin page and the recently viewed public page.

Switcher

Switcher between the recently viewed admin page and the recently viewed public page.

Non Cache Public Post Preview vs Switcher