Based on the graphical multi

代码说明：

基于图形化的多线程下载器，可实现添加，暂停，删除等功能，里面的代码逻辑划分的不错，新手可以参考参考-Based on the graphical multi-threaded download, and can be add, pause, delete, and other functions, the code inside the logic of the division of good, and newcomers can refer to reference