.NET 中 AsyncLocal 的实现原理及丢失上下文问题

1.实现原理

　　https://www.cnblogs.com/eventhorizon/p/12240767.html

2.丢失上下文相关解答

https://github.com/davidfowl/AspNetCoreDiagnosticScenarios/blob/master/AsyncGuidance.md#avoid-setting-asynclocalt-values-outside-of-async-methods

https://stackoverflow.com/questions/43391498/asynclocal-value-is-null-after-being-set-from-within-application-beginrequest

https://stackoverflow.com/questions/50968004/asynclocal-with-asp-net-core-controller-serviceproviderscope

https://github.com/dotnet/aspnetcore/issues/3249

https://blog.stephencleary.com/2016/12/eliding-async-await.html

https://blog.stephencleary.com/2013/04/implicit-async-context-asynclocal.html