code: def close(self):
          
          if self.is_open:
              message_input = UnityMessage()
              message_input.header.status = 400
              self.unity_to_external.parent_conn.send(message_input)
              self.unity_to_external.parent_conn.close()
              self.server.stop(False)
              self.is_open = False
docs: Sends a shutdown signal to the unity environment, and closes the grpc connection.