using System;

using System.Net;

using System.Net.Http;

using Polly;

public class Program

{

    public static void Main()

    {

        var shouldHandle = new PredicateBuilder<HttpResponseMessage>()

            .HandleResult(r => r.StatusCode == HttpStatusCode.InternalServerError);

​

        var pipeline = new ResiliencePipelineBuilder<HttpResponseMessage>()

            .AddFallback(new()

                         {

                             ShouldHandle = shouldHandle,

                             FallbackAction = static args => Outcome.FromResultAsValueTask(ResolveFallbackResponse(args.Outcome))

                         })

            .AddRetry(new()

                      {

                          ShouldHandle = shouldHandle,

                          MaxRetryAttempts = 3,

                          Delay = TimeSpan.FromSeconds(0.5),

                      })

            .Build();

​

        var result = pipeline.Execute(() => new HttpResponseMessage(HttpStatusCode.InternalServerError));

        result.StatusCode.Dump();

    }

​

    static HttpResponseMessage ResolveFallbackResponse(Outcome<HttpResponseMessage> outcome)

        => new HttpResponseMessage(HttpStatusCode.RequestTimeout);

}