getIdToken method
Implementation
Future<String> getIdToken(String smsCode) async {
// Authentication with Firebase
if (FirebaseAuth.instance.currentUser != null)
return FirebaseAuth.instance.currentUser!.getIdToken();
AuthCredential credentials = PhoneAuthProvider.credential(
verificationId: _verificationId, smsCode: smsCode);
UserCredential userCredential =
await FirebaseAuth.instance.signInWithCredential(credentials);
if (userCredential == null) return '';
_idToken = await userCredential.user!.getIdToken();
return _idToken;
}