[bugfix] optimize windows threadpool destroy order, thanks Ryan.

README.md

@@ -309,7 +309,7 @@ int main() {
 * Thanks to the recommendation from [awesome-cpp](https://github.com/fffaraz/awesome-cpp), we all know, it is the most authoritative recommendation list for cpp project in the world
 * Thanks to the recommendation from `Taskflow Group`: [awesome-parallel-computing](https://github.com/taskflow/awesome-parallel-computing), and we always treat [taskflow](https://github.com/taskflow/taskflow) as a role model
 * Thanks to the recommendation from [awesome-workflow-engines](https://github.com/meirwah/awesome-workflow-engines)
-* 感谢 [@yangyuxiang77](https://github.com/yangyuxiang77) [@logerrors](https://github.com/logerrors) [@whenever5225](https://github.com/whenever5225) [@May-Yaha](https://github.com/May-Yaha) [@Codesire-Deng](https://github.com/Codesire-Deng) [@yeshenyong](https://github.com/yeshenyong) [@MirrorYuChen](https://github.com/MirrorYuChen) [@HanYa](https://github.com/CodingHanYa) 等朋友（以贡献时间先后为序）为项目做出的贡献
+* 感谢 [@yangyuxiang77](https://github.com/yangyuxiang77) [@logerrors](https://github.com/logerrors) [@whenever5225](https://github.com/whenever5225) [@May-Yaha](https://github.com/May-Yaha) [@Codesire-Deng](https://github.com/Codesire-Deng) [@yeshenyong](https://github.com/yeshenyong) [@MirrorYuChen](https://github.com/MirrorYuChen) [@HanYa](https://github.com/CodingHanYa) [@Ryan](https://github.com/ryanhuang) 等朋友（以贡献时间先后为序）为项目做出的贡献
 * 感谢所有为`CGraph`项目提出的意见和建议的朋友，在此不一一提及。随时欢迎大家加入，一起共建
 
 </details>

src/UtilsCtrl/ThreadPool/UThreadPool.cpp

@@ -137,12 +137,18 @@ CStatus UThreadPool::destroy() {
     for (auto &pt : primary_threads_) {
         status += pt->destroy();        
     }
+    CGRAPH_FUNCTION_CHECK_STATUS
 
-	for (auto &pt : primary_threads_) {        
+    /**
+     * 这里之所以 destroy和 delete分开两个循环执行，
+     * 是因为当前线程被delete后，还可能存在未被delete的主线程，来steal当前线程的任务
+     * 在windows环境下，可能出现问题。
+     * destroy 和 delete 分开之后，不会出现此问题。
+     * 感谢 Ryan大佬(https://github.com/ryanhuang) 提供的帮助
+     */
+    for (auto &pt : primary_threads_) {
         CGRAPH_DELETE_PTR(pt)
     }
-
-    CGRAPH_FUNCTION_CHECK_STATUS
     primary_threads_.clear();
 
     // secondary 线程是智能指针，不需要delete

src/UtilsCtrl/UAllocator.h

@@ -16,8 +16,6 @@
 
 CGRAPH_NAMESPACE_BEGIN
 
-static std::mutex g_session_mtx;
-
 /**
  * 仅用于生成CObject类型的类
  */