FutureOrValueCallback<T>  typedef 
 
        FutureOrValueCallback<T> =
     FutureOr<void>  Function(T value)
     
    
    
Implementation
typedef FutureOrValueCallback<T> = FutureOr<void> Function(T value);typedef FutureOrValueCallback<T> = FutureOr<void> Function(T value);