public boolean isEmpty() {
    return byZoom.values().stream().noneMatch(e -> e > 0);
  }
Load tile weights from a gzipped TSV file with {@code z, x, y, loads} columns.
<p>
Duplicate entries will be added together. If the file is missing, will fall back to embedded file with top 50k OSM
tiles.
planetiler-core/src/main/java/com/onthegomap/planetiler/util/TileWeights.java