It lets you track message at certain points in their life cycle by invoking custom code from user exits while the message is passing through the message flow.

它允许您在消息通过消息流传递时调用用户出口中的自定义代码，从而在消息生命周期中的某个点跟踪消息。

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At the node level you can track the passing of the message from one node to the other. Consider the following example scenario.

在节点级别，您可以跟踪消息从一个节点到另一个节点的传递。

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Most people regard overtaking as meaning cars passing each other on the track, during the race.

我们通常认为的超车仍然是赛车在赛道上的超越。

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Equally important, passing fast-track offers America's politicians a rare opportunity to help poorer countries while also helping themselves.

ECONOMIST: Trade

In the photograph taken by a high school student from a bus passing by the track the double amputee is seen from some distance wearing his blades and dark lycra running clothes and is walking on a track with his hands on his hips.

NPR: Newspaper Publishes Photo Of Pistorius In Blades

About 4km to the east, just outside of Las Galeras, I ventured off the tarmac roads and walked along a dirt track, passing both roaming horses and scooters carrying entire families.

BBC: Lodges Robinson Crusoe would love