Custom track shape for flutter slider widget without height

custom_track_shape.dart

import 'package:flutter/material.dart';

class CustomTrackShape extends RoundedRectSliderTrackShape {
  @override
  Rect getPreferredRect(
      {required RenderBox parentBox,
      Offset offset = Offset.zero,
      required SliderThemeData sliderTheme,
      bool isEnabled = false,
      bool isDiscrete = false}) {
    final double? trackHeight = sliderTheme.trackHeight;
    final double? trackLeft = offset.dx;
    final double? trackTop =
        offset.dy + (parentBox.size.height - trackHeight!) / 2;
    final double? trackWidth = parentBox.size.width;
    return Rect.fromLTWH(trackLeft!, trackTop!, trackWidth!, trackHeight);
  }
}