Real time Data tracker (MB statistics_) and cache speed booster

Whenever we load a site, can we have a tracker which tells us how much MB a site is consuming ?

and also cache booster, we should have an option to store cache aggressively so that site loads faster.

if i had a google doc 35 pages long, everytime i load instead of storing cache locally on my computer, google loads everything from servers from scratch, it wastes time and data for every load, so it would be better if you work on a new tech to improve load time and make a site to forcefully store cache in local machine and load it faster.