Browsers and cloudflare workers removed/neutered high resolution timers (and things from which you can build high resolution timers) to make exploitation diffic

Browsers and cloudflare workers removed/neutered high resolution timers (and things from which you can build high resolution timers) to make exploitation difficult. CPU speculates past the bounds check and loads values you should not read into cache and you try to find out which value was loaded into cache using precise timing but the timer is imprecise so you don't know what the value was which you were not supposed to be able to read.