paint method
Paints this render object into the given context at offset.
Implementation
@override
void paint(PaintingContext context, Offset offset) {
_ensureStylesCached();
final int w = size!.width;
final int trackWidth = _trackWidth(w);
final int thumbPos = _thumbPosition(trackWidth);
_paintTrack(context, offset.x, offset.y, trackWidth, thumbPos);
if (label != null && label!.isNotEmpty) {
_paintLabel(context, offset.x + trackWidth + 2, offset.y);
}
}