Ensure that the execution batching provider is disposed. (#7831)

Author: michaelstaib

src/HotChocolate/Core/src/Fetching/BatchScheduler.cs

@@ -17,6 +17,7 @@ public sealed class BatchScheduler : IBatchHandler
     private readonly List<Func<ValueTask>> _tasks = [];
     private bool _dispatchOnSchedule;
     private readonly List<EventHandler> _listeners = [];
+    private bool _disposed;
 
     /// <inheritdoc />
     public event EventHandler TaskEnqueued
@@ -219,4 +220,13 @@ private async Task DispatchOnEnqueue(Func<ValueTask> dispatch)
             _semaphore.Release();
         }
     }
+
+    public void Dispose()
+    {
+        if (!_disposed)
+        {
+            _semaphore.Dispose();
+            _disposed = true;
+        }
+    }
 }

src/HotChocolate/Core/src/Fetching/IBatchHandler.cs

@@ -5,4 +5,4 @@ namespace HotChocolate.Fetching;
 /// <summary>
 /// The execution engine batch scheduler and dispatcher.
 /// </summary>
-public interface IBatchHandler : IBatchDispatcher, IBatchScheduler;
+public interface IBatchHandler : IBatchDispatcher, IBatchScheduler, IDisposable;