Transient objects are always different; a new instance is provided to every controller and every service.
Scoped objects are the same within a request, but different across different requests.
Singleton objects are the same for every object and every request.
权重：
AddSingleton→AddTransient→AddScoped
AddSingleton的生命周期：
项目启动-项目关闭 相当于静态类 只会有一个
AddScoped的生命周期：
请求开始-请求结束 在这次请求中获取的对象都是同一个
AddTransient的生命周期：
请求获取-（GC回收-主动释放） 每一次获取的对象都不是同一个
AddTransient, AddScoped and AddSingleton Services Differences
