title: Using ToListAsync() with Automapper ProjectToQueryable()
body: <p>I have a sync method which I'm trying to convert to async. Basically, the code below projects the data into a DTO, and selects rows and orders them based on properties of the DTO. It also gets only a certain 'page' of the data.</p>
  
  <pre><code>return GetDbContext().Items
              .ProjectToQueryable&lt;DTO&gt;(automapperConfigProvider)
              .Where({expression based on DTO})
              .OrderBy({expression based on DTO}).ThenBy(...)
              .Skip(skip)
              .Take(take)
              .ToList();
  </code></pre>
  
  <p>I tried to convert it like this but it fails on the <code>ToListAsync</code>.</p>
  
  <pre><code>var query = GetDbContext().Items
              .ProjectToQueryable&lt;DTO&gt;(automapperConfigProvider)
              .Where({expression based on DTO})
              .OrderBy({expression based on DTO}).ThenBy(...)
              .Skip(skip)
              .Take(take);
  return await query.ToListAsync();
  </code></pre>
  
  <p>The exception I get is:</p>
  
  <p>The source IQueryable doesn't implement IDbAsyncEnumerable. Only sources that implement IDbAsyncEnumerable can be used for Entity Framework asynchronous operations. For more details see <a href="http://go.microsoft.com/fwlink/?LinkId=287068" rel="nofollow">http://go.microsoft.com/fwlink/?LinkId=287068</a>.</p>
  
  <p>I'm using EntityFramework, so the link in the exception does not make sense to me.</p>
  
  <p>Has anyone encountered this?</p>