@Override
    public List<MetricFamilySamples> collect() {
      GaugeMetricFamily postGcPoolSizes = new GaugeMetricFamily(
        "jvm_memory_pool_post_gc_bytes_total",
        "Memory used by each pool after last GC",
        List.of("pool")
      );
      for (var entry : ProcessInfo.getPostGcPoolSizes().entrySet()) {
        postGcPoolSizes.addMetric(List.of(entry.getKey()), entry.getValue());
      }
      return List.of(postGcPoolSizes);
    }
Reports stats on post-GC memory consumption of each memory pool.
planetiler-core/src/main/java/com/onthegomap/planetiler/stats/PrometheusStats.java