title: Recommended way to convert IGrouping<TKey, TValue> to IDictionary<TKey, IEnumerable<TValue>>
body: <p>This has got to be a duplicate, but my searching is not yielding the results I want.</p>
  
  <p>It seems this should be fairly straightforward, but no built-in LINQ mechanism seems to be in place to make this happen.  Some help would be appreciated.</p>
  
  <p>...it's also possible I'm doing this wrong.  I have an enumerable set of objects with a property <code>Foo</code> that I want to create a dictionary with the <code>Foo</code> property the key of a dictionary, where the value is an enumeration of objects having <code>Foo</code> as the same value.</p>