title: Using Polly for a retry attempt from an async function
body: <p>I'm trying to retry a failed operation 3 times.</p>
  <p>I'm using Polly for a retry operation.</p>
  <p>I want to get the exception in case the retry operation fails and retry again 2 times and so on.</p>
  <pre><code>return await Policy
             .Handle&lt;CustomException&gt;()
             .RetryAsync(3, onRetryAsync: async (exception, retryCount, context) =&gt;
             {
                 return await runner.run(params);
             });
  </code></pre>
  <p>The function should return</p>
  <pre><code>Task&lt;IReadOnlyCollection&lt;string&gt;&gt;
  </code></pre>
  <p>I'm getting the following error:</p>
  <blockquote>
  <p>async lambda expression converted to a task returning delegate cannot
  return a value</p>
  </blockquote>