docs: void collectStats(final StatsCollector collector) {
      collector.record("compaction.count", compaction_count);
      collector.record("compaction.duplicates", duplicates_same, "type=identical");
      collector.record("compaction.duplicates", duplicates_different, "type=variant");
      if (!tsdb.config.enable_compactions()) {
        return;
      }
      // The remaining stats only make sense with compactions enabled.
      collector.record("compaction.queue.size", size);
      collector.record("compaction.errors", handle_read_error.errors, "rpc=read");
      collector.record("compaction.errors", handle_write_error.errors, "rpc=put");
      collector.record("compaction.errors", handle_delete_error.errors,
                       "rpc=delete");
      collector.record("compaction.writes", written_cells);
      collector.record("compaction.deletes", deleted_cells);
    }