Added components to article

lib/feature/authentication/bloc/auth_state.dart

@@ -7,6 +7,10 @@ class Unauthenticated extends AuthState {
   Unauthenticated({this.sessionExpired = false});
 }
 
+/// Transient state while [SetAuthenticatedEvent] is being processed and the
+/// user info is being fetched from the server.
+class Authenticating extends AuthState {}
+
 class Authenticated extends AuthState {
   User user;
   String sessionId;