title: How to determine when NSURLSessionTask's request begins?
body: <p>I use <code>NSURLSessionTask</code>s and I'm trying to monitor how long some of my HTTP Requests take, what delegate method (or something else) can I monitor for when the <code>NSURLSessionTask</code> actually makes the initial request?  If this were a <code>NSURLConnection</code> inside an <code>NSOperation</code> I'd just start a timer when I start the request but I don't have control over when tasks start.</p>