1.Gets a value that indicates whether the object can be made unmodifiable.
获取一个值，该值指示是否可将对象变为不可修改。
2.Returns an unmodifiable Map of general request properties for this connection.
返回此连接的通用请求属性的不可更改映射。
3.Causes these young people patient to accept this unmodifiable fact with difficulty.
使这些青少年患者难以接受这一不可改变的事实。
4.Returns an unmodifiable Map of the header fields.
返回头字段的不可更改映射。
5.Makes the current object unmodifiable and sets its IsFrozen property to true.
使当前对象变为不可修改并将其IsFrozen属性设置为true。