- Introduce a new DI friendly API for handling lifetime events. IApplicationLifetime isn't
isn't replaceable so we introduce a new DI friendly API that can be implemented to handle
lifetime events of an ASP.NET application. It should also make it possible to write up extension
on IWebHostBuilder to wire up to external systems that need to register the state of the application (like systemd).
- Run all handlers even if one throws
- Let both sets of event handlers run before throwing (IApplicationLifetimeEvents and IApplicationLifetime cancellation token callbacks).