DartDart_HandleFinalizerFunction typedef
        DartDart_HandleFinalizerFunction =
     void Function(Pointer<Void>  isolate_callback_data, Pointer<Void>  peer)
    
    
    
Implementation
typedef DartDart_HandleFinalizerFunction = void Function(
    ffi.Pointer<ffi.Void> isolate_callback_data, ffi.Pointer<ffi.Void> peer);