title: Polly WaitAndRetry with final exception does nothing
body: <p>I execute calls to an external service that is not very stable, and thus throws WebExceptions.<br>
  I want to retry a few times and after the last attempt I want to throw the last error received.</p>
  
  <p>This is my attempt with <a href="http://www.thepollyproject.org/" rel="nofollow noreferrer">Polly (v6.1.1)</a>:</p>
  
  <pre><code>public static Policy WaitAndRetryPolicy&lt;T&gt;(short nrOfRetryAttempts = 5) where T : Exception
  {
      var waitAndRetry = Policy
          .Handle&lt;T&gt;()
          .WaitAndRetry(nrOfRetryAttempts, retryAttempt =&gt; TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)));
  
      var fallbackForLastError = Policy
          .Handle&lt;T&gt;()
          .Fallback(
              fallbackAction: () =&gt; { },
              onFallback: (ex) =&gt; { throw ex; });
  
      return Policy.Wrap(fallbackForLastError, waitAndRetry);
  }
  </code></pre>
  
  <p>Caller, legacy VB.Net:</p>
  
  <pre><code>Dim retryPolicy = Policies.WaitAndRetryPolicy(Of WebException)()
  Dim theResult = retryPolicy.
      ExecuteAndCapture(Function()
                            Return aProxy.GetSomething(a, b)
                        End Function).Result
  </code></pre>
  
  <p>When I run the code as depicted above, <em>theResult</em> stays null and it seems like the service is not called.
  If I just use the WaitAndRetryPolicy without the <em>Fallback</em> function, the service is called and the retry mechanism works as expected (without throwing the exception of course).</p>
  
  <p>How can I achieve my goal, without having to check <em>PolicyResult.FinalException</em> in the caller code?</p>