code: def shutdown(self):
          
  
          # Remove ourself from the dictionary of running managers
          try:
              del self._running_managers[self._manager_key]
          except KeyError:
              pass
  
          # Kill the listening thread
          self._listen_thread.kill()
  
          # Close all the connections
          for conn in self.tendrils.values():
              conn.close()
  
          # Ensure all data is appropriately reset
          self.tendrils = {}
          self.running = False
          self._local_addr = None
          self._local_addr_event.clear()
          self._listen_thread = None
docs: Unconditionally shuts the TendrilManager down, killing all
          threads and closing all tendrils.