Implement HedgingResilienceStrategy

.github/dependabot.yml

@@ -24,3 +24,4 @@ updates:
     - dependency-name: "Microsoft.Extensions.Logging"
     - dependency-name: "System.Diagnostics.DiagnosticSource"
     - dependency-name: "System.Threading.RateLimiting"
+    - dependency-name: "Microsoft.Bcl.AsyncInterfaces"

src/Directory.Packages.props

@@ -4,6 +4,7 @@
     <PackageVersion Include="BenchmarkDotNet" Version="0.13.5" />
     <PackageVersion Include="FluentAssertions" Version="6.10.0" />
     <PackageVersion Include="GitHubActionsTestLogger" Version="2.0.1" />
+    <PackageVersion Include="Microsoft.Bcl.AsyncInterfaces" Version="1.0.0" />
     <PackageVersion Include="Microsoft.CodeAnalysis.NetAnalyzers" Version="7.0.1" />
     <PackageVersion Include="Microsoft.Extensions.Caching.Memory" Version="7.0.0" />
     <PackageVersion Include="Microsoft.Extensions.DependencyInjection" Version="7.0.0" />
@@ -34,4 +35,4 @@
     <PackageVersion Include="Microsoft.Extensions.Options" Version="2.2.0" />
     <PackageVersion Include="Microsoft.Extensions.Logging.Abstractions" Version="2.2.0" />
   </ItemGroup>
-</Project>
+</Project>

src/Polly.Core.Tests/Hedging/Controller/HedgingControllerTests.cs

@@ -0,0 +1,36 @@
+using Polly.Hedging;
+using Polly.Hedging.Utils;
+
+namespace Polly.Core.Tests.Hedging.Controller;
+
+public class HedgingControllerTests
+{
+    [Fact]
+    public async Task Pooling_Ok()
+    {
+        var handler = new HedgingHandler().SetHedging<int>(handler => handler.HedgingActionGenerator = args => null).CreateHandler();
+        var controller = new HedgingController(new HedgingTimeProvider(), handler!, 3);
+
+        var context1 = controller.GetContext(ResilienceContext.Get());
+        await PrepareAsync(context1);
+
+        var context2 = controller.GetContext(ResilienceContext.Get());
+        await PrepareAsync(context2);
+
+        controller.RentedContexts.Should().Be(2);
+        controller.RentedExecutions.Should().Be(2);
+
+        context1.Complete();
+        context2.Complete();
+
+        controller.RentedContexts.Should().Be(0);
+        controller.RentedExecutions.Should().Be(0);
+    }
+
+    private static async Task PrepareAsync(HedgingExecutionContext context)
+    {
+        await context.LoadExecutionAsync((_, _) => new ValueTask<int>(10), "state");
+        await context.TryWaitForCompletedExecutionAsync(HedgingStrategyOptions.InfiniteHedgingDelay);
+        context.Tasks[0].AcceptOutcome();
+    }
+}