Deprecated unused property [RectangularSliderTrackShape.disabledThumbGapWidth] (#65246)

packages/flutter/lib/src/material/slider_theme.dart

@@ -1495,6 +1495,10 @@ class RectangularSliderTrackShape extends SliderTrackShape with BaseSliderTrackS
   /// the thumb and any part of the track when the slider is enabled. The
   /// Material spec defaults this gap width 2, which is half of the disabled
   /// thumb radius.
+  @Deprecated(
+    'It no longer has any effect because the thumb does not shrink when the slider is disabled now. '
+    'This feature was deprecated after v1.5.7.'
+  )
   final double disabledThumbGapWidth;
 
   @override