I have a fixed BottomNavigationBar with 4 items as described below.

How can I set the color of the selected item?

I've tried with: fixedColor and selectedItemColor but it would't work. 

```
BottomNavigationBar(
            type: BottomNavigationBarType.fixed,
            fixedColor: Colors.blue,
            //selectedItemColor: Colors.blue,
            currentIndex: snapshot.data.index,
            onTap: _bottomNavBarBloc.pickItem,
            items: [
              BottomNavigationBarItem(
                icon: Icon(
                  Icons.access_time,
                  color: Colors.black,
                ),
              ),
              BottomNavigationBarItem(...),
              BottomNavigationBarItem(...),
              BottomNavigationBarItem(...),
            ]);

```