static <T> ZoomFunction<T> fromMaxZoomThresholds(Map<Integer, ? extends T> thresholds) {
    return fromMaxZoomThresholds(thresholds, null);
  }
Returns a zoom function that returns the value from the next higher key in {@code thresholds} or {@code null} if
over the max key.
planetiler-core/src/main/java/com/onthegomap/planetiler/util/ZoomFunction.java