不可变属性的存取器将总是具有值引用，因而调用的任何一方都不需要防御性复制，这使得它们效率更高。
Accessors for immutable properties will always have value semantics and do not need the defensive copying on either side of the call, making them more efficient.
之前提到过存取器访问如何比直接访问慢，这例子说明，某些语言约会定导致不可见的性能问题。
Earlier we talked about how accessors are slower than direct field accesses, so this is an example of a certain language idiom resulting in an "invisible" performance hit.
当有线网络不可使用时，如在战场通讯和紧急救援等任务中，移动自组网络提供了一种可行的地面通信和信息存取技术。
When wired networks are not available, as in battlefield communication and emergency search-and-rescue scenarios, MANETs provide a feasible way for communication and information access.
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