One question about this: currently, whenever the histogram is reset, it's associated `_count` metric is reset too. People had thought they would get a counter metric for free when using a histogram, but if it gets reset every couple of minutes or even more frequently, it becomes very unreliable and less useful for things like rate calculations. It might even get reset twice between scrapes if you have a high scrape interval and low purge interval, and then it becomes completely useless.

So: should we tell people to not depend on this metric for anything useful, or should we change it in such a way that it never gets reset?