一个计时器的类，利用CPU内部的一个高分辨率计数器计数实现，可以用于各种精确计时的场合，尤其适合需要测试某段代码的运行时间的情况-like a timer, using the CPU of a high-resolution internal Counting realized, could be used for various occasions precision timing, especially for the need to test a certain code of the running time