title: How to register polly in startup file in .net core 2.2?
body: <p>I am implementing polly in my .net core 2.2 application. For HttpClient there is a nuget Microsoft.Extenstions.Http.Polly which can to used to register any polly pattern (circuit breaker or retry) in startup. But how can I used polly for other exceptions like "SqlException". 
  Just take an example of this chunk:</p>
  
  <pre><code>        Policy
          .Handle&lt;SqlException&gt;(ex =&gt; ex.Number == (int)SqlHandledExceptions.DatabaseNotCurrentlyAvailable)
          .CircuitBreakerAsync(
              // number of exceptions before breaking circuit
              exceptionsAllowedBeforeBreaking,
              // time circuit opened before retry
              TimeSpan.FromSeconds(30),
              OnBreak,
              OnReset,
              OnHalfOpen)
          .WithPolicyKey($"F1.{PolicyKeys.SqlCircuitBreakerAsyncPolicy}"),
  </code></pre>
  
  <p>I want to register this policy in startup file to handle sql exception. How can I do this?</p>