'Get the room state after the given event
Args:
event(synapse.events.EventBase): event of interest
Returns:
A Deferred map from ((type, state_key)->Event)'

@defer.inlineCallbacks
def get_state_after_event(self, event):

    state_ids = (yield self.store.get_state_ids_for_event(event.event_id))
    if event.is_state():
        state_ids = state_ids.copy()
        state_ids[(event.type, event.state_key)] = event.event_id
    defer.returnValue(state_ids)
