FutureOrValue2Callback<A, B>  typedef 
 
        FutureOrValue2Callback<A, B> =
     FutureOr<void>  Function(A value1, B value2)
     
    
    
Implementation
typedef FutureOrValue2Callback<A, B> = FutureOr<void> Function(
  A value1,
  B value2,
);