docs: public static double cosineFormulaRad(double lat1, double lon1, double lat2, double lon2) {
      if(lat1 == lat2 && lon1 == lon2) {
        return 0.;
      }
      final DoubleWrapper tmp = new DoubleWrapper(); // To return cosine
      final double slat1 = sinAndCos(lat1, tmp), clat1 = tmp.value;
      final double slat2 = sinAndCos(lat2, tmp), clat2 = tmp.value;
      final double a = slat1 * slat2 + clat1 * clat2 * cos(lon2 - lon1);
      return a < .9999_9999_9999_999 ? acos(a) : 0;
    }