title: How OWIN hooks on ASP.NET startup
body: <p>I've been browsing and googling about how did things like OWIN hooks on the ASP.NET activities.</p>
  
  <p>I know if we create a self hosted OWIN, we will call it manually and it is clear that we are calling OWIN to make it start running.</p>
  
  <p>However, I see that OWIN is automatically invoked when ASP.NET started without the need of calling webapp start or anything else. OWIN just hook into ASP.NET and act as an interceptor on each request.</p>
  
  <p>My example would be signalr, we call the mapping of signalr in OWIN configuration method. However, I dont see anything that could possibly call OWIN configuration method. But signalr is already mapped and works.</p>
  
  <p>How did OWIN hooks on ASP.NET activities? Is it OWIN who register the hooks or ASP.NET who now recognize OWIN and call automatically?</p>