init method
Implementation
init(String? apiKey) async {
if(apiKey != null && apiKey.isNotEmpty){
_idTokenListener = ()=> loadDataFromApi();
_dateMovementsListener = ()=> _loadMovements();
idToken.addListener(_idTokenListener!);
dateMovements.addListener(_dateMovementsListener!);
await _authenticate(apiKey);
} else {
await dispose();
}
}