introduce method
Implementation
void introduce(String navigation, CupertinoStackViewState cupertinoStackViewState) {
if (_isMapped(navigation)) {
_map.firstWhere((_ListPair navigationStackStatePair) => navigationStackStatePair._navigation == navigation)._cupertinoStackViewState = cupertinoStackViewState;
} else {
_map.insert(0, _ListPair(navigation, cupertinoStackViewState));
}
}