issue facing in implementation of substateStream

[vishant-jaiswal]

store .substateStream<UserState>((AppState appState) => appState.user) .listen((onData) { print("user changed"); });

above line is giving me following compile time error any suggestion how to get away with this

Error: The function expression type '(#lib1::AppState) → #lib2::UserState' isn't of expected type '(#lib3::Built<dynamic, dynamic>) → #lib2::UserState'. Change the type of the function expression or the context in which it is used. .substateStream<UserState>((AppState appState) => appState.user)