- Consistently enumerate stream aggregation outputs in alphabetical order across the source code and docs.
This should simplify future maintenance of the corresponding code and docs.
- Fix the link to `rate_sum()` at `see also` section of `rate_avg()` docs.
- Make more clear the docs for `rate_sum()` and `rate_avg()` outputs.
- Encapsulate output metric suffix inside rateAggrState. This eliminates possible bugs related
to incorrect suffix passing to newRateAggrState().
- Rename rateAggrState.total field to less misleading rateAggrState.increase name, since it calculates
counter increase in the current aggregation window.
- Set rateLastValueState.prevTimestamp on the first sample in time series instead of the second sample.
This makes more clear the code logic.
- Move the code for removing outdated entries at rateAggrState into removeOldEntries() function.
This make the code logic inside rateAggrState.flushState() more clear.
- Do not write output sample with zero value if there are no input series, which could be used
for calculating the rate, e.g. if only a single sample is registered for every input series.
- Do not take into account input series with a single registered sample when calculating rate_avg(),
since this leads to incorrect results.
- Move {rate,total}AggrState.flushState() function to the end of rate.go and total.go files, so they look more similar.
This shuld simplify future mantenance.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/6243