title: What's the difference between Windows.System.Threading.ThreadPool and System.Threading.ThreadPool?
body: <p>The Windows Phone 8 SDK documentation doesn't describe a difference between <code>Windows.System.Threading.ThreadPool</code> and <code>System.Threading.ThreadPool</code>.  Is there any difference between the two besides the obvious API difference? For example, do they use the same pool of threads? If there is an underlying difference, which should I use and when?</p>