linkAccount method
Link an additional provider credential to the current (anonymous
or identified) account. NEW in 4.0.
Returns the resulting AuthResult (the upgraded user). For
social providers, credential is the identity / id token; for
email/password, the server-defined credential shape applies.
Implementation
Future<Map<String, dynamic>> linkAccount(
String provider, String credential) async {
final result =
_expectJson(_bindings.authLinkAccount(provider, credential));
_notifyAuthState(_sessionFromAuthResult(result));
return result;
}