Adopt System.TimeProvider

src/Directory.Packages.props

@@ -4,7 +4,8 @@
     <PackageVersion Include="BenchmarkDotNet" Version="0.13.5" />
     <PackageVersion Include="FluentAssertions" Version="6.11.0" />
     <PackageVersion Include="GitHubActionsTestLogger" Version="2.1.0" />
-    <PackageVersion Include="Microsoft.Bcl.AsyncInterfaces" Version="1.0.0" />
+    <PackageVersion Include="Microsoft.Bcl.AsyncInterfaces" Version="6.0.0" />
+    <PackageVersion Include="Microsoft.Bcl.TimeProvider" Version="8.0.0-preview.4.23259.5" />
     <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" />

src/Polly.Core.Tests/Hedging/HedgingTimeProvider.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Threading.Tasks;
-using Polly.Utils;
 
 namespace Polly.Core.Tests.Hedging;
 
@@ -25,15 +24,16 @@ public void Advance(TimeSpan diff)
 
     public List<DelayEntry> DelayEntries { get; } = new List<DelayEntry>();
 
-    public override DateTimeOffset UtcNow => _utcNow;
+    public override DateTimeOffset GetUtcNow() => _utcNow;
 
-    public override void CancelAfter(CancellationTokenSource source, TimeSpan delay)
+    public override ITimer CreateTimer(TimerCallback callback, object? state, TimeSpan dueTime, TimeSpan period)
     {
-        throw new NotSupportedException();
+        return base.CreateTimer(callback, state, dueTime, period);
     }
 
     public override Task Delay(TimeSpan delayValue, CancellationToken cancellationToken = default)
     {
+
         var entry = new DelayEntry(delayValue, new TaskCompletionSource<bool>(), _utcNow.Add(delayValue));
         cancellationToken.Register(() => entry.Source.TrySetCanceled(cancellationToken));
         DelayEntries.Add(entry);

src/Polly.Core/CircuitBreaker/Controller/CircuitStateController.cs

@@ -272,7 +272,7 @@ private void CloseCircuit_NeedsLock<TResult>(Outcome<TResult> outcome, bool manu
 
     private bool PermitHalfOpenCircuitTest_NeedsLock()
     {
-        var now = _timeProvider.UtcNow;
+        var now = _timeProvider.GetUtcNow();
         if (now >= _blockedUntil)
         {
             _blockedUntil = now + _breakDuration;
@@ -307,7 +307,7 @@ private void OpenCircuit_NeedsLock<TResult>(Outcome<TResult> outcome, bool manua
     private void OpenCircuitFor_NeedsLock<TResult>(Outcome<TResult> outcome, TimeSpan breakDuration, bool manual, ResilienceContext context, out Task? scheduledTask)
     {
         scheduledTask = null;
-        var utcNow = _timeProvider.UtcNow;
+        var utcNow = _timeProvider.GetUtcNow();
 
         _blockedUntil = IsDateTimeOverflow(utcNow, breakDuration) ? DateTimeOffset.MaxValue : utcNow + breakDuration;
 

src/Polly.Core/CircuitBreaker/Health/RollingHealthMetrics.cs

@@ -44,7 +44,7 @@ public override HealthInfo GetHealthInfo()
 
     private HealthWindow UpdateCurrentWindow()
     {
-        var now = TimeProvider.UtcNow;
+        var now = TimeProvider.GetUtcNow();
         if (_currentWindow == null || now - _currentWindow.StartedAt >= _windowDuration)
         {
             _currentWindow = new()

src/Polly.Core/CircuitBreaker/Health/SingleHealthMetrics.cs

@@ -15,7 +15,7 @@ public SingleHealthMetrics(TimeSpan samplingDuration, TimeProvider timeProvider)
         : base(timeProvider)
     {
         _samplingDuration = samplingDuration;
-        _startedAt = timeProvider.UtcNow;
+        _startedAt = timeProvider.GetUtcNow();
     }
 
     public override void IncrementSuccess()
@@ -32,7 +32,7 @@ public override void IncrementFailure()
 
     public override void Reset()
     {
-        _startedAt = TimeProvider.UtcNow;
+        _startedAt = TimeProvider.GetUtcNow();
         _successes = 0;
         _failures = 0;
     }
@@ -46,7 +46,7 @@ public override HealthInfo GetHealthInfo()
 
     private void TryReset()
     {
-        if (TimeProvider.UtcNow - _startedAt >= _samplingDuration)
+        if (TimeProvider.GetUtcNow() - _startedAt >= _samplingDuration)
         {
             Reset();
         }

src/Polly.Core/Hedging/Controller/HedgingController.cs

@@ -15,7 +15,7 @@ public HedgingController(TimeProvider provider, HedgingHandler.Handler handler,
         _executionPool = new ObjectPool<TaskExecution>(() =>
         {
             Interlocked.Increment(ref _rentedExecutions);
-            return new TaskExecution(handler);
+            return new TaskExecution(handler, provider);
         },
         _ =>
         {

src/Polly.Core/Hedging/Controller/TaskExecution.cs

@@ -23,11 +23,16 @@ internal sealed class TaskExecution
 {
     private readonly ResilienceContext _cachedContext = ResilienceContext.Get();
     private readonly HedgingHandler.Handler _handler;
+    private readonly TimeProvider _timeProvider;
     private CancellationTokenSource? _cancellationSource;
     private CancellationTokenRegistration? _cancellationRegistration;
     private ResilienceContext? _activeContext;
 
-    public TaskExecution(HedgingHandler.Handler handler) => _handler = handler;
+    public TaskExecution(HedgingHandler.Handler handler, TimeProvider timeProvider)
+    {
+        _handler = handler;
+        _timeProvider = timeProvider;
+    }
 
     /// <summary>
     /// Gets the task that represents the execution of the hedged task.
@@ -81,7 +86,7 @@ public async ValueTask<bool> InitializeAsync<TResult, TState>(
         int attempt)
     {
         Type = type;
-        _cancellationSource = CancellationTokenSourcePool.Get();
+        _cancellationSource = CancellationTokenSourcePool.Get(TimeSpan.Zero, _timeProvider);
         Properties.Replace(snapshot.OriginalProperties);
 
         if (snapshot.OriginalCancellationToken.CanBeCanceled)

src/Polly.Core/Hedging/HedgingResilienceStrategy.cs

@@ -5,7 +5,6 @@
 using Polly.Hedging;
 using Polly.Hedging.Utils;
 using Polly.Strategy;
-using Polly.Utils;
 
 namespace Polly;
 

src/Polly.Core/Polly.Core.csproj

@@ -24,6 +24,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Condition="!$([MSBuild]::IsTargetFrameworkCompatible($(TargetFramework), 'netcoreapp3.1'))" />
+    <PackageReference Include="Microsoft.Bcl.TimeProvider" />
     <PackageReference Include="System.Threading.Tasks.Extensions" Condition="!$([MSBuild]::IsTargetFrameworkCompatible($(TargetFramework), 'netcoreapp3.1'))" />
     <PackageReference Include="System.ValueTuple" Condition="$([MSBuild]::GetTargetFrameworkIdentifier('$(TargetFramework)')) == '.NETFramework'" />
     <PackageReference Include="System.ComponentModel.Annotations" Condition="!$([MSBuild]::IsTargetFrameworkCompatible($(TargetFramework), 'netcoreapp3.1'))" />

src/Polly.Core/Timeout/TimeoutResilienceStrategy.cs

@@ -35,8 +35,7 @@ protected internal override async ValueTask<TResult> ExecuteCoreAsync<TResult, T
         }
 
         var previousToken = context.CancellationToken;
-        var cancellationSource = CancellationTokenSourcePool.Get();
-        _timeProvider.CancelAfter(cancellationSource, timeout);
+        var cancellationSource = CancellationTokenSourcePool.Get(timeout, _timeProvider);
         context.CancellationToken = cancellationSource.Token;
 
         CancellationTokenRegistration? registration = null;

src/Polly.Core/Utils/CancellationTokenSourcePool.cs

@@ -1,3 +1,6 @@
+using System.Threading;
+using System.Threading.Tasks;
+
 namespace Polly.Utils
 {
     internal static class CancellationTokenSourcePool
@@ -7,12 +10,24 @@ internal static class CancellationTokenSourcePool
             static () => new CancellationTokenSource(),
             static cts => true);
 #endif
-        public static CancellationTokenSource Get()
+        public static CancellationTokenSource Get(TimeSpan delay, TimeProvider timeProvider)
         {
 #if NET6_0_OR_GREATER
-            return Pool.Get();
+            if (timeProvider != TimeProvider.System)
+            {
+                return timeProvider.CreateCancellationTokenSource(delay);
+            }
+
+            // we are only polling sources when system time provider is used
+            var pooledSource = Pool.Get();
+            if (delay != System.Threading.Timeout.InfiniteTimeSpan)
+            {
+                pooledSource.CancelAfter(delay);
+            }
+
+            return pooledSource;
 #else
-            return new CancellationTokenSource();
+            return timeProvider.CreateCancellationTokenSource(delay);
 #endif
         }