trigger auth_state_hook prior to options form

- allow auth_state_hook to be async
- trigger it prior to start and options_form serving, rather than on home page

jupyterhub/user.py

@@ -535,12 +535,17 @@ class User:
         # trigger pre-spawn hook on authenticator
         authenticator = self.authenticator
         try:
+            spawner._start_pending = True
+
             if authenticator:
                 # pre_spawn_start can thow errors that can lead to a redirect loop
                 # if left uncaught (see https://github.com/jupyterhub/jupyterhub/issues/2683)
                 await maybe_future(authenticator.pre_spawn_start(self, spawner))
 
-            spawner._start_pending = True
+            # trigger auth_state hook
+            auth_state = await self.get_auth_state()
+            await spawner.run_auth_state_hook(auth_state)
+
             # update spawner start time, and activity for both spawner and user
             self.last_activity = (
                 spawner.orm_spawner.started