I have really strange problem. The thing is it seems that Cloudflare Rocket Loader doesn't work on mobile devices, but works perfectly on desktops.
My website is loading for less than a 1 sec on desktops and for more than 12 secs(!) on mobile devices.
I checked Networking in Chrome dev tools.
This is what's happens on desktop:
And this is on Android device:
It seems that Rocket Loader is just ignoring everything. What could be the problem?
RocketLoader is still in beta so can be a bit bugger. The better alternative is to enable HTTP/2 which has the benefit of multiplexing and a single connection whilst also having other benefits such as Server Push and Header Compression.
To get HTTP/2 on Cloudflare, all you need to do to enable SSL on your site (such as by setting an "Always Use HTTPS" Page Rule in Cloudflare).