This calculates how much a counter increases over a given period of time, which is the area under the curve of it's rate. increase(x[5m]) is equivilent to rate(x[5m]) * 300.
changes() takes a range vector and returns the number of times a value has changed in the given time window for each time series as an instant vector.
resets() returns for every range vector element how many counter resets there have been in the specified range.