pub fn percentile(&self, percentile: u64) -> (Duration, Duration) {
        let lower_gap_float = self.total as f64 * percentile as f64 / 100.0;
        let lower_gap = lower_gap_float.round() as usize;
        debug_assert!(lower_gap <= self.total);

        let mut amount = 0;
        for (range_start, current_amount) in &self.histogram {
            amount += current_amount;

            if amount >= lower_gap {
                let (range_start, range_end) = self.full_range_for(*range_start);
                return (
                    Duration::from_millis(range_start),
                    Duration::from_millis(range_end),
                );
            }
        }

        unreachable!("Range for {} percentile was not found", percentile);
    }
Returns the time range for the requested distribution percentile.
core/tests/loadnext/src/report_collector/metrics_collector.rs