Firebase Authentication

await FirebaseAuth.instance.verifyPhoneNumber(
  phoneNumber: '+44 7123 123 456',
  verificationCompleted: (PhoneAuthCredential credential) {},
  verificationFailed: (FirebaseAuthException e) {},
  codeSent: (String verificationId, int? resendToken) {},
  codeAutoRetrievalTimeout: (String verificationId) {},
);