title: Use 'Average()' On EF CORE (C# .NET CORE)
body: <p>I use .NET CORE for a while now
  and i noticed that some queries run really strange, so i did some profiling and i noticed that some queries and running in parts on the database, instead of getting it in 1 shot.
  So i turned off the option 'QueryClientEvaluation' from EF core and i keep getting error</p>
  
  <pre><code>  The LINQ expression 'Average()' could not be translated and will be evaluated locally.
  </code></pre>
  
  <p>which is very strange because i used the <code>Average</code> function in EF6 till now with no issue, so why should it need to use QueryClientEvaluation??</p>
  
  <p>here is a simple sample <code>_context.Reviews.Select(r =&gt; r.Rating).Average()</code></p>