paint method
Implementation
@override
void paint(PaintingContext context, Offset offset) {
final totalPadding = padding ?? const EdgeInsets.all(0);
final width = size!.width;
final height = size!.height;
_ensureStylesCached();
final TextStyle borderStyle = _cachedBorderStyle!;
_paintBackground(context, offset, width, height);
_paintChild(context, offset, totalPadding);
_paintTopBorder(context, offset, width, borderStyle);
_paintSideBorders(context, offset, width, height, borderStyle);
_paintBottomBorder(context, offset, width, height, borderStyle);
}