title: Does let clause in parallel linq force the parallel evaluation?
body: <p>On the xamarin iOS site there is the following parallel linq example.</p>
  
  <pre><code>from item in items.AsParallel ()
     let result = DoExpensiveWork (item)
     select result;
  </code></pre>
  
  <p>Could this not have been written </p>
  
  <pre><code>from item in items.AsParallel ()
     select DoExpensiveWork (item);
  </code></pre>
  
  <p>Or is there a reason for the let clause? Does this force it to be evaluated in parallel?</p>