No way to find out if Authenticator is waiting or failed

[Esam-Bustaty]

All examples that use authentication have something like:

while (!service.Authenticator.CanAuthenticate())
    yield return null;

The problem is that if an error has happened this will wait indefinitely, the co-routine never ends, and I cannot display a message for the user.

[Esam-Bustaty]

I created pr #33 to solve this.

[mamoonraja]

Hi @Esam-Bustaty , Thanks a lot for opening the PR, we will review it asap.