说明：  运用多线程的方法计算pi的值。通过公式法和面积法实现。可以通过调整线程数和数据的运算规模来计算pi，计算不同线程之间的性能差异。
(Calculated using multi-threaded the value of pi. Area through the formula and method implementation. You can adjust the number of threads and data operations to calculate the size of pi, calculate the difference in performance between the different threads.)