message: Native always passes a crumb
diff: @@ -7,9 +7,6 @@ class Scene extends React.Component {
  super(props);
  this.state = {navigationEvent: null};
  }
  - static defaultProps = {
  - crumb: 0
  - }
  static getDerivedStateFromProps(props) {
  var {crumb, navigationEvent} = props;
  var {state, crumbs} = navigationEvent.stateNavigator.stateContext;
  