void fetch(long id) {
    if (!visited.contains(id)) {
      visited.add(id);
      qidsToFetch.add(id);
    }
    if (qidsToFetch.size() >= batchSize) {
      flush();
    }
  }
Only pass elements that the profile cares about to next step in pipeline.
planetiler-core/src/main/java/com/onthegomap/planetiler/util/Wikidata.java