胡老师指路

• https://www.runoob.com/csharp/csharp-multithreading.html
• https://www.jianshu.com/p/c78a6a799059
• https://duoduokou.com/csharp/50803458847157628736.html
• https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/events/
• https://csharp.hotexamples.com/examples/-/PostEvent/-/php-postevent-class-examples.html
• https://docs.microsoft.com/zh-cn/dotnet/standard/events/how-to-raise-and-consume-events
• https://cn.bing.com/search?q=C%23+post+event&qs=n&form=QBRE&sp=-1&pq=c%23+&sc=10-3&sk=&cvid=C757662D02BE471885D03683CEEB5E7A&ghsh=0&ghacc=0&ghpl=