thanks for your feedback Tadeas Kriz

have thought about that during development, but because of the constraint of not using any external dependencies and because iOS doesn't offer some kind of out-of-the-box solution as Android (dim screen, show progress, undim and dismiss upon success/failure) have left it out. Personally in my projects I use [https://github.com/TransitApp/SVProgressHUD|SVProgressHUD] for all my progress needs, and I suspect many people do in their production applications. So my choice was, should I create something from scratch or not? I think, and can be wrong, would have been an overkill.

Regardless,
to circumvent the 'multiple simultaneously clicks', I have attached PR that disabled the login button when 'in-process' and enable it afterwards upon success/ failure respectively. Let me know what u think.