title: How to add documentation tooltip to classes, methods, properties, etc. in C#?
body: <p>Not sure if I'm even calling this right but I wanted to start adding some documentation to my classes, methods, properties, etc. I <em>know</em> this is probably super obvious but I never really learned it. I'm not sure where to start. </p>
  
  <p>Just to clarify whenever you roll over a class (or method, property, etc.) it shows a tooltip in Visual Studio with some documentation on that specific method.</p>
  
  <blockquote>
    <p><strong>class Microsoft.Phone.BackgroundAudio.BackgroundAudioPlayer</strong> <br/>
    Provides background access to audio playback functionality such as play, pause, fast-forward, and rewind.</p>
  </blockquote>
  
  <p>What is that called and how can I implement this in my C# application?</p>