First time authentication to save token/tokenSecret
You can use your email/password combination initially to retrieve an OAuth1 token/secret combination which you can use on to reauthenticate when reloading the application. You can use any persistent storage system such as https://pub.dev/packages/localstorage.
Afterwards you can use the stored tokenData to authenticate.
var res =await _sdk.authenticateWithToken(ParamsOauth1WithToken(token: storage.getItem('token'), tokenSecret: storage.getItem('tokenSecret')), (consents) {_onConsentNeeded(consents); },)