When a message is received, its header field values can be changed;

当接收到消息时，它的报头字段值是可以改变的；

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Header fields with multiple values are encoded into a single header field using a special delimiter (see Section 8.1.2.3), this preserves the relative order of values for that header field.

具有多个值的报头字段使用特定的分割器被编码分割到一个单独的报头区域(见章节8.1.2.3 HeaderOrdering)，这保留了该报头字段中各种值的对应顺序。

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