Anyone know how exactly that works?
I.e. if you get hit for 20% of your max hp over e.g. 2 seconds and get knocked down to 30% hr boost, what happens if you take more damage in the next 3 seconds, staying inside the initial 5s window?

Is that added to the original damage since it's inside a 5s window?
Is the window reset upon losing 30% Hr boost so taking damage after 2s actually means it starts to count from scratch towards 20% for the remaining Hr Boost?

Is there any cooldown for losing hr boost? Any cooldown for recovering hr boost with counters?
Are counters counted per enemy hit or per counter attack used?
Do counters recover hr boost if triggered, but not hitting any enemy (e.g. someone else killed the intended target first, etc.)?