refactor: Use ValueTask on plumbing methods

Switch to ValueTask on methods that are likely to complete
synchronously and/or be populated with contrib-/user-provided
delegates.

Signed-off-by: Austin Drenski <austin@austindrenski.io>

README.md

@@ -295,25 +295,25 @@ To satisfy the interface, all methods (`BeforeAsync`/`AfterAsync`/`FinallyAsync`
 ```csharp
 public class MyHook : Hook
 {
-  public Task<EvaluationContext> BeforeAsync<T>(HookContext<T> context,
+  public ValueTask<EvaluationContext> BeforeAsync<T>(HookContext<T> context,
       IReadOnlyDictionary<string, object> hints = null, CancellationToken cancellationToken = default)
   {
     // code to run before flag evaluation
   }
 
-  public virtual Task AfterAsync<T>(HookContext<T> context, FlagEvaluationDetails<T> details,
+  public virtual ValueTask AfterAsync<T>(HookContext<T> context, FlagEvaluationDetails<T> details,
       IReadOnlyDictionary<string, object> hints = null, CancellationToken cancellationToken = default)
   {
     // code to run after successful flag evaluation
   }
 
-  public virtual Task ErrorAsync<T>(HookContext<T> context, Exception error,
+  public virtual ValueTask ErrorAsync<T>(HookContext<T> context, Exception error,
       IReadOnlyDictionary<string, object> hints = null, CancellationToken cancellationToken = default)
   {
     // code to run if there's an error during before hooks or during flag evaluation
   }
 
-  public virtual Task FinallyAsync<T>(HookContext<T> context, IReadOnlyDictionary<string, object> hints = null, CancellationToken cancellationToken = default)
+  public virtual ValueTask FinallyAsync<T>(HookContext<T> context, IReadOnlyDictionary<string, object> hints = null, CancellationToken cancellationToken = default)
   {
     // code to run after all other stages, regardless of success/failure
   }

src/OpenFeature/Api.cs

@@ -44,7 +44,7 @@ private Api() { }
         /// <remarks>The provider cannot be set to null. Attempting to set the provider to null has no effect.</remarks>
         /// <param name="featureProvider">Implementation of <see cref="FeatureProvider"/></param>
         /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
-        public async Task SetProviderAsync(FeatureProvider featureProvider, CancellationToken cancellationToken = default)
+        public async ValueTask SetProviderAsync(FeatureProvider featureProvider, CancellationToken cancellationToken = default)
         {
             this.EventExecutor.RegisterDefaultFeatureProvider(featureProvider);
             await this._repository.SetProviderAsync(featureProvider, this.GetContext(), cancellationToken: cancellationToken).ConfigureAwait(false);
@@ -58,7 +58,7 @@ public async Task SetProviderAsync(FeatureProvider featureProvider, Cancellation
         /// <param name="clientName">Name of client</param>
         /// <param name="featureProvider">Implementation of <see cref="FeatureProvider"/></param>
         /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
-        public async Task SetProviderAsync(string clientName, FeatureProvider featureProvider, CancellationToken cancellationToken = default)
+        public async ValueTask SetProviderAsync(string clientName, FeatureProvider featureProvider, CancellationToken cancellationToken = default)
         {
             this.EventExecutor.RegisterClientFeatureProvider(clientName, featureProvider);
             await this._repository.SetProviderAsync(clientName, featureProvider, this.GetContext(), cancellationToken: cancellationToken).ConfigureAwait(false);
@@ -206,7 +206,7 @@ public EvaluationContext GetContext()
         /// </para>
         /// </summary>
         /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
-        public async Task ShutdownAsync(CancellationToken cancellationToken = default)
+        public async ValueTask ShutdownAsync(CancellationToken cancellationToken = default)
         {
             await this._repository.ShutdownAsync(cancellationToken: cancellationToken).ConfigureAwait(false);
             await this.EventExecutor.ShutdownAsync(cancellationToken).ConfigureAwait(false);

src/OpenFeature/EventExecutor.cs

@@ -11,7 +11,7 @@
 namespace OpenFeature
 {
 
-    internal delegate Task ShutdownDelegate(CancellationToken cancellationToken);
+    internal delegate ValueTask ShutdownDelegate(CancellationToken cancellationToken);
 
     internal class EventExecutor
     {
@@ -327,7 +327,7 @@ private void InvokeEventHandler(EventHandlerDelegate eventHandler, Event e)
             }
         }
 
-        public async Task ShutdownAsync(CancellationToken cancellationToken = default)
+        public async ValueTask ShutdownAsync(CancellationToken cancellationToken = default)
         {
             await this._shutdownDelegate(cancellationToken).ConfigureAwait(false);
         }
@@ -338,7 +338,7 @@ internal void SetShutdownDelegate(ShutdownDelegate del)
         }
 
         // Method to signal shutdown
-        private async Task SignalShutdownAsync(CancellationToken cancellationToken)
+        private async ValueTask SignalShutdownAsync(CancellationToken cancellationToken)
         {
             // Enqueue a shutdown signal
             await this.EventChannel.Writer.WriteAsync(new ShutdownSignal(), cancellationToken).ConfigureAwait(false);

src/OpenFeature/FeatureProvider.cs

@@ -125,10 +125,10 @@ public abstract Task<ResolutionDetails<Value>> ResolveStructureValueAsync(string
         /// the <see cref="GetStatus"/> method after initialization is complete.
         /// </para>
         /// </remarks>
-        public virtual Task InitializeAsync(EvaluationContext context, CancellationToken cancellationToken = default)
+        public virtual ValueTask InitializeAsync(EvaluationContext context, CancellationToken cancellationToken = default)
         {
             // Intentionally left blank.
-            return Task.CompletedTask;
+            return new ValueTask();
         }
 
         /// <summary>
@@ -137,10 +137,10 @@ public virtual Task InitializeAsync(EvaluationContext context, CancellationToken
         /// </summary>
         /// <returns>A task that completes when the shutdown process is complete.</returns>
         /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
-        public virtual Task ShutdownAsync(CancellationToken cancellationToken = default)
+        public virtual ValueTask ShutdownAsync(CancellationToken cancellationToken = default)
         {
             // Intentionally left blank.
-            return Task.CompletedTask;
+            return new ValueTask();
         }
 
         /// <summary>

src/OpenFeature/Hook.cs

@@ -30,10 +30,10 @@ public abstract class Hook
         /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
         /// <typeparam name="T">Flag value type (bool|number|string|object)</typeparam>
         /// <returns>Modified EvaluationContext that is used for the flag evaluation</returns>
-        public virtual Task<EvaluationContext> BeforeAsync<T>(HookContext<T> context,
+        public virtual ValueTask<EvaluationContext> BeforeAsync<T>(HookContext<T> context,
             IReadOnlyDictionary<string, object> hints = null, CancellationToken cancellationToken = default)
         {
-            return Task.FromResult(EvaluationContext.Empty);
+            return new ValueTask<EvaluationContext>(EvaluationContext.Empty);
         }
 
         /// <summary>
@@ -44,10 +44,10 @@ public virtual Task<EvaluationContext> BeforeAsync<T>(HookContext<T> context,
         /// <param name="hints">Caller provided data</param>
         /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
         /// <typeparam name="T">Flag value type (bool|number|string|object)</typeparam>
-        public virtual Task AfterAsync<T>(HookContext<T> context, FlagEvaluationDetails<T> details,
+        public virtual ValueTask AfterAsync<T>(HookContext<T> context, FlagEvaluationDetails<T> details,
             IReadOnlyDictionary<string, object> hints = null, CancellationToken cancellationToken = default)
         {
-            return Task.CompletedTask;
+            return new ValueTask();
         }
 
         /// <summary>
@@ -58,10 +58,10 @@ public virtual Task AfterAsync<T>(HookContext<T> context, FlagEvaluationDetails<
         /// <param name="hints">Caller provided data</param>
         /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
         /// <typeparam name="T">Flag value type (bool|number|string|object)</typeparam>
-        public virtual Task ErrorAsync<T>(HookContext<T> context, Exception error,
+        public virtual ValueTask ErrorAsync<T>(HookContext<T> context, Exception error,
             IReadOnlyDictionary<string, object> hints = null, CancellationToken cancellationToken = default)
         {
-            return Task.CompletedTask;
+            return new ValueTask();
         }
 
         /// <summary>
@@ -71,9 +71,9 @@ public virtual Task ErrorAsync<T>(HookContext<T> context, Exception error,
         /// <param name="hints">Caller provided data</param>
         /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
         /// <typeparam name="T">Flag value type (bool|number|string|object)</typeparam>
-        public virtual Task FinallyAsync<T>(HookContext<T> context, IReadOnlyDictionary<string, object> hints = null, CancellationToken cancellationToken = default)
+        public virtual ValueTask FinallyAsync<T>(HookContext<T> context, IReadOnlyDictionary<string, object> hints = null, CancellationToken cancellationToken = default)
         {
-            return Task.CompletedTask;
+            return new ValueTask();
         }
     }
 }

src/OpenFeature/OpenFeatureClient.cs

@@ -256,7 +256,7 @@ private async Task<FlagEvaluationDetails<T>> EvaluateFlagAsync<T>(
             return evaluation;
         }
 
-        private async Task<HookContext<T>> TriggerBeforeHooksAsync<T>(IReadOnlyList<Hook> hooks, HookContext<T> context,
+        private async ValueTask<HookContext<T>> TriggerBeforeHooksAsync<T>(IReadOnlyList<Hook> hooks, HookContext<T> context,
             FlagEvaluationOptions options, CancellationToken cancellationToken = default)
         {
             var evalContextBuilder = EvaluationContext.Builder();
@@ -280,7 +280,7 @@ private async Task<HookContext<T>> TriggerBeforeHooksAsync<T>(IReadOnlyList<Hook
             return context.WithNewEvaluationContext(evalContextBuilder.Build());
         }
 
-        private async Task TriggerAfterHooksAsync<T>(IReadOnlyList<Hook> hooks, HookContext<T> context,
+        private async ValueTask TriggerAfterHooksAsync<T>(IReadOnlyList<Hook> hooks, HookContext<T> context,
             FlagEvaluationDetails<T> evaluationDetails, FlagEvaluationOptions options, CancellationToken cancellationToken = default)
         {
             foreach (var hook in hooks)
@@ -289,7 +289,7 @@ private async Task TriggerAfterHooksAsync<T>(IReadOnlyList<Hook> hooks, HookCont
             }
         }
 
-        private async Task TriggerErrorHooksAsync<T>(IReadOnlyList<Hook> hooks, HookContext<T> context, Exception exception,
+        private async ValueTask TriggerErrorHooksAsync<T>(IReadOnlyList<Hook> hooks, HookContext<T> context, Exception exception,
             FlagEvaluationOptions options, CancellationToken cancellationToken = default)
         {
             foreach (var hook in hooks)
@@ -305,7 +305,7 @@ private async Task TriggerErrorHooksAsync<T>(IReadOnlyList<Hook> hooks, HookCont
             }
         }
 
-        private async Task TriggerFinallyHooksAsync<T>(IReadOnlyList<Hook> hooks, HookContext<T> context,
+        private async ValueTask TriggerFinallyHooksAsync<T>(IReadOnlyList<Hook> hooks, HookContext<T> context,
             FlagEvaluationOptions options, CancellationToken cancellationToken = default)
         {
             foreach (var hook in hooks)

src/OpenFeature/ProviderRepository.cs

@@ -55,7 +55,7 @@ internal class ProviderRepository
         /// </param>
         /// <param name="afterShutdown">called after a provider is shutdown, can be used to remove event handlers</param>
         /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
-        public async Task SetProviderAsync(
+        public async ValueTask SetProviderAsync(
             FeatureProvider featureProvider,
             EvaluationContext context,
             Action<FeatureProvider> afterSet = null,
@@ -98,7 +98,7 @@ await InitProviderAsync(this._defaultProvider, context, afterInitialization, aft
                 .ConfigureAwait(false);
         }
 
-        private static async Task InitProviderAsync(
+        private static async ValueTask InitProviderAsync(
             FeatureProvider newProvider,
             EvaluationContext context,
             Action<FeatureProvider> afterInitialization,
@@ -148,7 +148,7 @@ private static async Task InitProviderAsync(
         /// </param>
         /// <param name="afterShutdown">called after a provider is shutdown, can be used to remove event handlers</param>
         /// <param name="cancellationToken">The <see cref="CancellationToken"/>.</param>
-        public async Task SetProviderAsync(string clientName,
+        public async ValueTask SetProviderAsync(string clientName,
             FeatureProvider featureProvider,
             EvaluationContext context,
             Action<FeatureProvider> afterSet = null,
@@ -198,7 +198,7 @@ public async Task SetProviderAsync(string clientName,
         /// <remarks>
         /// Shutdown the feature provider if it is unused. This must be called within a write lock of the _providersLock.
         /// </remarks>
-        private async Task ShutdownIfUnusedAsync(
+        private async ValueTask ShutdownIfUnusedAsync(
             FeatureProvider targetProvider,
             Action<FeatureProvider> afterShutdown,
             Action<FeatureProvider, Exception> afterError,
@@ -226,7 +226,7 @@ private async Task ShutdownIfUnusedAsync(
         /// it would not be meaningful to emit an error.
         /// </para>
         /// </remarks>
-        private static async Task SafeShutdownProviderAsync(FeatureProvider targetProvider,
+        private static async ValueTask SafeShutdownProviderAsync(FeatureProvider targetProvider,
             Action<FeatureProvider> afterShutdown,
             Action<FeatureProvider, Exception> afterError,
             CancellationToken cancellationToken)
@@ -267,7 +267,7 @@ public FeatureProvider GetProvider(string clientName)
                 : this.GetProvider();
         }
 
-        public async Task ShutdownAsync(Action<FeatureProvider, Exception> afterError = null, CancellationToken cancellationToken = default)
+        public async ValueTask ShutdownAsync(Action<FeatureProvider, Exception> afterError = null, CancellationToken cancellationToken = default)
         {
             var providers = new HashSet<FeatureProvider>();
             this._providersLock.EnterWriteLock();

test/OpenFeature.E2ETests/Steps/EvaluationStepDefinitions.cs

@@ -42,7 +42,7 @@ public EvaluationStepDefinitions(ScenarioContext scenarioContext)
         {
             _scenarioContext = scenarioContext;
             var flagdProvider = new FlagdProvider();
-            Api.Instance.SetProviderAsync(flagdProvider).Wait();
+            Api.Instance.SetProviderAsync(flagdProvider).GetAwaiter().GetResult();
             client = Api.Instance.GetClient();
         }
 

test/OpenFeature.Tests/ClearOpenFeatureInstanceFixture.cs

@@ -7,7 +7,7 @@ public ClearOpenFeatureInstanceFixture()
         {
             Api.Instance.SetContext(null);
             Api.Instance.ClearHooks();
-            Api.Instance.SetProviderAsync(new NoOpFeatureProvider()).Wait();
+            Api.Instance.SetProviderAsync(new NoOpFeatureProvider()).GetAwaiter().GetResult();
         }
     }
 }