Timeout on zmq to allow gracefull exit

trap/prediction_server.py

@@ -242,6 +242,11 @@ class PredictionServer:
             if self.config.predict_training_data:
                 input_dict = eval_scene.get_clipped_input_dict(timestep, hyperparams['state'])
             else:
+                zmq_ev = self.trajectory_socket.poll(timeout=3)
+                if not zmq_ev:
+                    # on no data loop so that is_running is checked
+                    continue
+
                 data = self.trajectory_socket.recv()
                 frame: Frame = pickle.loads(data)
                 trajectory_data = frame.trajectories # TODO: properly refractor