message: add cardinality
diff: @@ -449,6 +449,7 @@ string QueryProfiler::ToJSON() const {
  ss << " \"name\": \"Query\", \n";
  ss << " \"result\": " + to_string(main_query.Elapsed()) + ",\n";
  ss << " \"timing\": " + to_string(main_query.Elapsed()) + ",\n";
  + ss << " \"cardinality\": " + to_string(root->info.elements) + ",\n";
  ss << " \"extra-info\": \"" + StringUtil::Replace(query, "\n", "\\n") + "\", \n";
  // print the phase timings
  ss << " \"timings\": [\n";
  