StateBuilder<T>  constructor 
      const
      StateBuilder<T> ({ 
    
    
- Key? key,
- required T initialValue,
- void onDispose()?,
- void onUpdate(- T
 
- required StateBuilderBuilder<T> builder,
Implementation
const StateBuilder({
  Key? key,
  required this.initialValue,
  this.onDispose,
  this.onUpdate,
  required this.builder,
}) : super(key: key);