draw method
Implementation of the parent class to draw the cross
Implementation
@override
void draw(Canvas canvas, FlSpot spot, Offset offsetInCanvas) {
final path = Path()
..moveTo(offsetInCanvas.dx, offsetInCanvas.dy)
..relativeMoveTo(-size / 2, -size / 2)
..relativeLineTo(size, size)
..moveTo(offsetInCanvas.dx, offsetInCanvas.dy)
..relativeMoveTo(size / 2, -size / 2)
..relativeLineTo(-size, size);
final paint = Paint()
..style = PaintingStyle.stroke
..strokeWidth = width
..color = color;
canvas.drawPath(path, paint);
}