verify method
Implementation
@override
Future<ApplicationVerificationResult> verify(
FirebaseAuth auth, String nonce) async {
var p = Platform.current;
if (p is IOsPlatform || p is MacOsPlatform) {
var v = await verifyWithApns(auth);
if (v != null) return ApplicationVerificationResult.apns(v);
} else if (p is AndroidPlatform) {
var v = await verifyWithSafetyNet(auth, nonce);
if (v != null) return ApplicationVerificationResult.safetyNet(v);
}
var v = await verifyWithRecaptcha(auth);
return ApplicationVerificationResult.recaptcha(v);
}