Using react-navigation with react-native.
How can jeg run a function at the end of animation?
So I want callback like 

```
navigate('RoadObject', () => { at the end of animationto do something... });

```

My tab navigator:

```
const MainNavigator = TabNavigator({
  Map: { 
    screen: MapScreen
  },
  RoadObject: { 
    screen: RoadObjectScreen
  }
},
{
  animationEnabled: true
});

```