dispose method
To dispose the objects.
Implementation
@override
void dispose() {
_fillPath.reset();
_strokePath.reset();
_drawIndexes.clear();
_highPoints.clear();
_lowPoints.clear();
_oldHighPoints.clear();
_oldLowPoints.clear();
_xValues.clear();
_topValues.clear();
_bottomValues.clear();
super.dispose();
}