better_view_error_handling.kt

fun onViewCreated() {
 disposables += viewModel.observeLoginResult()
   .observeOnMainThread()
   .subscribe {
     when (it) {
       is LoginResult.LoginOk -> finishLogin()
       is LoginResult.LoginError -> {
         when (it.error) {
           is NoInternetConnectionException -> showNoConnectionError()
           is InvalidCredentialsException -> showInvalidCredentialsError()
           is GeneralServerException -> showGeneralServerError()
           is ValidationException -> showValidationErrors(it.error.errors)
           is UnexpectedException -> unexpectedError() // crash?
         }
       }
     }
   }
}