AnimatedChildValueBuilder<T>  typedef 
 
        AnimatedChildValueBuilder<T> =
     Widget Function(BuildContext context, T oldValue, T newValue, double t, Widget? child)
     
    
A callback that builds a widget with raw animation progress information.
Used by AnimatedValueBuilder.raw to provide complete animation state including
the old value, new value, and current progress t between them (0.0 to 1.0).
This gives maximum control for custom interpolation and transition effects.
Implementation
typedef AnimatedChildValueBuilder<T> = Widget Function(
    BuildContext context, T oldValue, T newValue, double t, Widget? child);