Improved the stability of this task.

src/Squidex.Infrastructure.MongoDb/MongoDb/MongoExtensions.cs

@@ -160,20 +160,25 @@ namespace Squidex.Infrastructure.MongoDb
         }
 
         public static async Task ForEachPipelineAsync<TDocument>(this IAsyncCursor<TDocument> source, Func<TDocument, Task> processor, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            using (var selfToken = new CancellationTokenSource())
+            {
+                using (var combined = CancellationTokenSource.CreateLinkedTokenSource(selfToken.Token, cancellationToken))
                 {
                     var actionBlock =
-                new ActionBlock<TDocument>(processor,
+                        new ActionBlock<TDocument>(async x =>
+                            {
+                                if (!combined.IsCancellationRequested)
+                                {
+                                    await processor(x);
+                                }
+                            },
                             new ExecutionDataflowBlockOptions
                             {
                                 MaxDegreeOfParallelism = 1,
                                 MaxMessagesPerTask = 1,
                                 BoundedCapacity = 100
                             });
-
-            using (var selfToken = new CancellationTokenSource())
-            {
-                using (var combined = CancellationTokenSource.CreateLinkedTokenSource(selfToken.Token, cancellationToken))
-                {
                     try
                     {
                         await source.ForEachAsync(async i =>

tests/Squidex.Infrastructure.Tests/MongoDb/MongoExtensionsTests.cs

@@ -151,6 +151,7 @@ namespace Squidex.Infrastructure.MongoDb
                     }
 
                     result.Add(x);
+
                     return TaskHelper.Done;
                 }, cts.Token);
             });