title: What, if any, is the resource penalty for using System.Diagnostics.Stopwatch?
body: <p>For example</p>
  
  <pre><code>foo() //Some operation bound by an external resource. db,I/O, whatever.
  </code></pre>
  
  <p>vs.</p>
  
  <pre><code>var watch = new Stopwatch();
  watch.Start();
  foo()
  var time = watch.ElapsedMilliseconds
  watch.Stop();
  </code></pre>