Commented Issue: Flow the TimedOutToken and ClientDisconnectedToken [858]

With [this commit](http://aspnetwebstack.codeplex.com/SourceControl/changeset/c18dbd8306a2), it's now possible to flow the following two CancellationToken objects through the ASP.NET Web API pipeline under ASP.NET host:

```
public override Task ProcessRequestAsync(HttpContext context) {

CancellationTokenSource cancellationTokenSource = CancellationTokenSource.CreateLinkedTokenSource(
context.Request.TimedOutToken,
context.Response.ClientDisconnectedToken);

//...

}
```
Comments: Hi Hongmei, yep, makes more sense. Also, are u aware of the bug on ClientDisconnectedToken that I mentioned below as comment?