private void removeFilledRange(int x, IntRangeSet yRange) {
    if (yRange == null || yRange.isEmpty()) {
      return;
    }
    if (filledRanges == null) {
      filledRanges = new HashMap<>();
    }
    IntRangeSet existing = filledRanges.get(x);
    if (existing != null) {
      existing.removeAll(yRange);
    }
  }
Splits an entire vertical X column of edge segments into Y rows that form (X, Y) tile coordinates at this zoom
level, stores the result in {@link #tileContents} and returns the Y ranges of filled tile coordinates if this is a
polygon.
planetiler-core/src/main/java/com/onthegomap/planetiler/render/TiledGeometry.java