invalidateSession method
Invalidates the current user session, removes local session data, and
clears Session token request header in Fetcher.
If signInRedirect is specified in ClientOptions
when creating the Altogic api client and if the client is running
in a browser, redirects the user to the sign in page.
Implementation
Future<void> invalidateSession() async {
await _deleteLocalData();
_fetcher.clearSession();
_singInRedirect?.call();
}