1、Install-Package Microsoft.Owin.Host.SystemWeb
OWIN server that enables OWIN-based applications to run on IIS using the ASP.NET request pipeline.
依赖于IIS，需要配置MVC使用
2、Install-Package Microsoft.AspNet.WebApi.OwinSelfHost
This package allows you to host ASP.NET Web API within your own process using the OWIN HttpListener server.
ASP.NET Web API is a framework that makes it easy to build HTTP services that reach a broad range of clients, including browsers and mobile devices.
ASP.NET Web API is an ideal platform for building RESTful applications on the .NET Framework.
自宿主，不需要依赖IIS，构建WebAPI，即可使用http请求服务。
