title: F# and PLINQ extension methods
body: <p>While digging deeper into the latest release of F# I tried to have it interacting with PLINQ.
  I've noticed, however, that the two don't play very nice together code-wise.
  In fact it didn't seem possible to write code such as the following:</p>
  
  <pre><code>
  open System.Linq
  let someArray = [|"abc"; "def"|]
  someArray.AsParallel().Count(new Func&lt;_,_&gt;(fun s -> s.Length = 3))
  </code></pre>
  
  <p>because the extension methods for ParallelQuery contained in the System.Linq.ParallelEnumerable class didn't seem to get picked up by F#.<br/>
  I wouldn't be surprised if there were no support for extension methods at all, but since I can access the someArray.Count extension method defined for IEnumerable I wonder why can't I access those of PLINQ.<br/>
  Am I missing something?<br/>
  Is this an F# limitation? If so, is it by desing? If not, will it be addressed in a future release?</p>