某些字段可能看起来像全局定义的字段，但却是专用字段，只是名称正好相同。

It's possible that some of the fields that look like globally-defined fields are actually ad-hoc fields that happen to share the same name.

youdao

由于属性被不同的消息用来定义相关性数据，所以需要一种机制来允许指向表示这个属性的消息的专用字段。

Because a property is used by different messages to define correlation data, a mechanism is needed that allows pointing to a dedicated field of the message that represents this property.

youdao