What is Hedging strategy in Polly v8 and how to implement it in .NET?

Hedging executes additional concurrent attempts of an operation before the primary attempt finishes if it takes longer than expected. This decreases tail latency in high-availability systems.

Implementing Hedging with Polly

Hedging is ideal for idempotent operations (such as HTTP GET queries) where receiving the fastest successful response is critical.

Code Example

var pipeline = new ResiliencePipelineBuilder<HttpResponseMessage>()
    .AddHedging(new HedgingStrategyOptions<HttpResponseMessage>
    {
        MaxHedgedAttempts = 3,
        Delay = TimeSpan.FromMilliseconds(200),
        ShouldHandle = new PredicateBuilder<HttpResponseMessage>()
            .Handle<HttpRequestException>()
            .HandleResult(res => !res.IsSuccessStatusCode)
    })
    .Build();

var response = await pipeline.ExecuteAsync(async ct =>
{
    return await httpClient.GetAsync("https://api.example.com/data", ct);
});