refactor: remove dead code, arbitrary caps and unused API surface

- Remove GetPerformanceWarning: computed and immediately
  discarded in four constructors, never observable.
- Remove arbitrary validation caps (10,000 tasks, 10,000
  batch size, 24h timespan) that threw on legitimate large
  workloads. Negative/zero checks remain.
- Add missing parallelism/batch/timespan validation to the
  result processor variants so all processors behave alike.
- Strip unused equality ceremony, Deconstruct and
  AggressiveInlining (a no-op on async methods) from the
  TaskWrapper structs.
- Remove the completed-task fast paths in ParallelExtensions:
  rethrowing GetBaseException destroyed stack traces and
  dropped sibling exceptions; awaiting is equivalent and
  correct.
- LangVersion preview -> latest now that no preview features
  are used.
- Update README disposal notes to match the non-blocking
  synchronous Dispose.

Author: thomhurst

EnumerableAsyncProcessor.UnitTests/TaskWrapperStructValidationTests.cs

@@ -59,23 +59,6 @@ public async Task ItemTaskWrapper_ProcessesWithInput()
         await Assert.That(tcs.Task.IsCompletedSuccessfully).IsTrue();
     }
 
-    [Test]
-    public async Task TaskWrapper_EqualityWorks()
-    {
-        // Arrange
-        Func<Task> taskFactory = () => Task.CompletedTask;
-        var tcs = new TaskCompletionSource();
-        var wrapper1 = new ActionTaskWrapper(taskFactory, tcs);
-        var wrapper2 = new ActionTaskWrapper(taskFactory, tcs);
-        var wrapper3 = new ActionTaskWrapper(() => Task.CompletedTask, new TaskCompletionSource());
-
-        // Act & Assert
-        await Assert.That(wrapper1.Equals(wrapper2)).IsTrue();
-        await Assert.That(wrapper1 == wrapper2).IsTrue();
-        await Assert.That(wrapper1.Equals(wrapper3)).IsFalse();
-        await Assert.That(wrapper1 == wrapper3).IsFalse();
-    }
-
     [Test]
     public async Task TaskWrapper_ArrayStorage_WorksWithoutBoxing()
     {

EnumerableAsyncProcessor/EnumerableAsyncProcessor.csproj

@@ -4,7 +4,7 @@
         <TargetFrameworks>net6.0;net8.0;net9.0;netstandard2.0</TargetFrameworks>
         <ImplicitUsings>enable</ImplicitUsings>
         <Nullable>enable</Nullable>
-        <LangVersion>preview</LangVersion>
+        <LangVersion>latest</LangVersion>
         <Version>99.99.99</Version>
     </PropertyGroup>
 

EnumerableAsyncProcessor/Extensions/ParallelExtensions.cs

@@ -83,20 +83,8 @@ private static async Task<TResult> ProcessAsync<TSource, TResult>(
             semaphoreAcquired = true;
 
             cancellationToken.ThrowIfCancellationRequested();
-            var task = taskSelector(item);
-            
-            // Fast-path optimization for already completed tasks
-            if (task.IsCompleted)
-            {
-                if (task.IsFaulted)
-                    throw task.Exception?.GetBaseException() ?? task.Exception!;
-                if (task.IsCanceled)
-                    throw new OperationCanceledException();
-                return task.Result;
-            }
 
-            // Await the task directly - it's already async so no need for Task.Run
-            return await task.ConfigureAwait(false);
+            return await taskSelector(item).ConfigureAwait(false);
         }
         finally
         {
@@ -121,20 +109,8 @@ private static async Task ProcessAsync<TSource>(
             semaphoreAcquired = true;
 
             cancellationToken.ThrowIfCancellationRequested();
-            var task = taskSelector(item);
-            
-            // Fast-path optimization for already completed tasks
-            if (task.IsCompleted)
-            {
-                if (task.IsFaulted)
-                    throw task.Exception?.GetBaseException() ?? task.Exception!;
-                if (task.IsCanceled)
-                    throw new OperationCanceledException();
-                return;
-            }
 
-            // Await the task directly - it's already async so no need for Task.Run
-            await task.ConfigureAwait(false);
+            await taskSelector(item).ConfigureAwait(false);
         }
         finally
         {

EnumerableAsyncProcessor/RunnableProcessors/ResultProcessors/ResultBatchAsyncProcessor_2.cs

@@ -1,4 +1,5 @@
 using EnumerableAsyncProcessor.RunnableProcessors.ResultProcessors.Abstract;
+using EnumerableAsyncProcessor.Validation;
 
 namespace EnumerableAsyncProcessor.RunnableProcessors.ResultProcessors;
 
@@ -9,6 +10,8 @@ public class ResultBatchAsyncProcessor<TInput, TOutput> : ResultAbstractAsyncPro
     internal ResultBatchAsyncProcessor(int batchSize, IEnumerable<TInput> items, Func<TInput, Task<TOutput>> taskSelector,
         CancellationTokenSource cancellationTokenSource) : base(items, taskSelector, cancellationTokenSource)
     {
+        ValidationHelper.ValidateBatchSize(batchSize);
+
         _batchSize = batchSize;
     }
 

EnumerableAsyncProcessor/RunnableProcessors/ResultProcessors/ResultRateLimitedParallelAsyncProcessor_1.cs

@@ -1,6 +1,7 @@
 
 using EnumerableAsyncProcessor.Extensions;
 using EnumerableAsyncProcessor.RunnableProcessors.ResultProcessors.Abstract;
+using EnumerableAsyncProcessor.Validation;
 
 namespace EnumerableAsyncProcessor.RunnableProcessors.ResultProcessors;
 
@@ -10,6 +11,8 @@ public class ResultRateLimitedParallelAsyncProcessor<TOutput> : ResultAbstractAs
 
     internal ResultRateLimitedParallelAsyncProcessor(int count, Func<Task<TOutput>> taskSelector, int levelsOfParallelism, CancellationTokenSource cancellationTokenSource) : base(count, taskSelector, cancellationTokenSource)
     {
+        ValidationHelper.ValidateParallelism(levelsOfParallelism);
+
         _levelsOfParallelism = levelsOfParallelism;
     }
 

EnumerableAsyncProcessor/RunnableProcessors/ResultProcessors/ResultRateLimitedParallelAsyncProcessor_2.cs

@@ -1,5 +1,6 @@
 using EnumerableAsyncProcessor.Extensions;
 using EnumerableAsyncProcessor.RunnableProcessors.ResultProcessors.Abstract;
+using EnumerableAsyncProcessor.Validation;
 
 namespace EnumerableAsyncProcessor.RunnableProcessors.ResultProcessors;
 
@@ -9,6 +10,8 @@ public class ResultRateLimitedParallelAsyncProcessor<TInput, TOutput> : ResultAb
 
     internal ResultRateLimitedParallelAsyncProcessor(IEnumerable<TInput> items, Func<TInput, Task<TOutput>> taskSelector, int levelsOfParallelism, CancellationTokenSource cancellationTokenSource) : base(items, taskSelector, cancellationTokenSource)
     {
+        ValidationHelper.ValidateParallelism(levelsOfParallelism);
+
         _levelsOfParallelism = levelsOfParallelism;
     }
 

EnumerableAsyncProcessor/RunnableProcessors/ResultProcessors/ResultTimedRateLimitedParallelAsyncProcessor_1.cs

@@ -1,5 +1,6 @@
 using EnumerableAsyncProcessor.Extensions;
 using EnumerableAsyncProcessor.RunnableProcessors.ResultProcessors.Abstract;
+using EnumerableAsyncProcessor.Validation;
 
 namespace EnumerableAsyncProcessor.RunnableProcessors.ResultProcessors;
 
@@ -10,6 +11,9 @@ public class ResultTimedRateLimitedParallelAsyncProcessor<TOutput> : ResultAbstr
 
     internal ResultTimedRateLimitedParallelAsyncProcessor(int count, Func<Task<TOutput>> taskSelector, int levelsOfParallelism, TimeSpan timeSpan, CancellationTokenSource cancellationTokenSource) : base(count, taskSelector, cancellationTokenSource)
     {
+        ValidationHelper.ValidateParallelism(levelsOfParallelism);
+        ValidationHelper.ValidateTimeSpan(timeSpan);
+
         _levelsOfParallelism = levelsOfParallelism;
         _timeSpan = timeSpan;
     }

EnumerableAsyncProcessor/RunnableProcessors/ResultProcessors/ResultTimedRateLimitedParallelAsyncProcessor_2.cs

@@ -1,5 +1,6 @@
 using EnumerableAsyncProcessor.Extensions;
 using EnumerableAsyncProcessor.RunnableProcessors.ResultProcessors.Abstract;
+using EnumerableAsyncProcessor.Validation;
 
 namespace EnumerableAsyncProcessor.RunnableProcessors.ResultProcessors;
 
@@ -10,6 +11,9 @@ public class ResultTimedRateLimitedParallelAsyncProcessor<TInput, TOutput> : Res
 
     internal ResultTimedRateLimitedParallelAsyncProcessor(IEnumerable<TInput> items, Func<TInput, Task<TOutput>> taskSelector, int levelsOfParallelism, TimeSpan timeSpan, CancellationTokenSource cancellationTokenSource) : base(items, taskSelector, cancellationTokenSource)
     {
+        ValidationHelper.ValidateParallelism(levelsOfParallelism);
+        ValidationHelper.ValidateTimeSpan(timeSpan);
+
         _levelsOfParallelism = levelsOfParallelism;
         _timeSpan = timeSpan;
     }