从安装的NuGet packages逆向找回去
<package id="Microsoft.AspNet.WebApi.Core" version="5.2.7" targetFramework="net472" />
检查下载的dll，是System.Web.Http.dll
https://www.nuget.org/packages/Microsoft.AspNet.WebApi.Core/
This package contains the core runtime assemblies for ASP.NET Web API.
This package is used by hosts of the ASP.NET Web API runtime.
To host a Web API in IIS use the Microsoft.AspNet.WebApi.WebHost package.
To host a Web API in your own process use the Microsoft.AspNet.WebApi.SelfHost package.
https://github.com/aspnet/AspNetWebStack/tree/master/src/System.Web.Http 源码对应的路径
测试 https://github.com/aspnet/AspNetWebStack/tree/master/test/System.Web.Http.Test
<package id="Microsoft.AspNet.WebApi.Owin" version="5.2.7" targetFramework="net472" />
检查下载的dll，是System.Web.Http.Owin.dll
https://www.nuget.org/packages/Microsoft.AspNet.WebApi.Owin/
This package allows you to host ASP.NET Web API within an OWIN server and provides access to additional OWIN features.
https://github.com/aspnet/AspNetWebStack/tree/master/src/System.Web.Http.Owin 源码对应的路径
测试 https://github.com/aspnet/AspNetWebStack/tree/master/test/System.Web.Http.Owin.Test
<package id="Microsoft.AspNet.WebApi.Client" version="5.2.7" targetFramework="net472" />
检查下载的dll，是System.Net.Http.Formatting.dll
https://www.nuget.org/packages/Microsoft.AspNet.WebApi.Client/
This package adds support for formatting and content negotiation to System.Net.Http. It includes support for JSON, XML, and form URL encoded data.
https://github.com/aspnet/AspNetWebStack/tree/master/src/System.Net.Http.Formatting