CSHARP-2225: ChangeStreamCursor MoveNext sometimes throws EndOfStreamException

Author: rstam

src/MongoDB.Driver.Core/Core/Operations/ChangeStreamCursor.cs

@@ -137,10 +137,8 @@ private bool CanResumeAfter(Exception exception)
         [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2202:Do not dispose objects multiple times")]
         private TDocument DeserializeDocument(RawBsonDocument rawDocument)
         {
-            var slice = rawDocument.Slice;
-            var bytes = slice.AccessBackingBytes(0);
-            using (var memoryStream = new MemoryStream(bytes.Array, bytes.Offset, bytes.Count))
-            using (var reader = new BsonBinaryReader(memoryStream))
+            using (var stream = new ByteBufferStream(rawDocument.Slice, ownsBuffer: false))
+            using (var reader = new BsonBinaryReader(stream))
             {
                 var context = BsonDeserializationContext.CreateRoot(reader);
                 return _documentSerializer.Deserialize(context);

tests/MongoDB.Driver.Core.Tests/Core/Operations/ChangeStreamOperationTests.cs

@@ -350,6 +350,49 @@ public void Execute_should_return_expected_results_for_inserts(
             }
         }
 
+        [SkippableTheory]
+        [ParameterAttributeData]
+        public void Execute_should_return_expected_results_for_large_batch(
+            [Values(1, 2, 3)] int numberOfChunks,
+            [Values(false, true)] bool async)
+        {
+            RequireServer.Check().Supports(Feature.ChangeStreamStage).ClusterTypes(ClusterType.ReplicaSet, ClusterType.Sharded);
+            EnsureDatabaseExists();
+            DropCollection();
+
+            var pipeline = new[] { BsonDocument.Parse("{ $match : { operationType : \"insert\" } }") };
+            var resultSerializer = new ChangeStreamDocumentSerializer<BsonDocument>(BsonDocumentSerializer.Instance);
+            var messageEncoderSettings = new MessageEncoderSettings();
+            var subject = new ChangeStreamOperation<ChangeStreamDocument<BsonDocument>>(_collectionNamespace, pipeline, resultSerializer, messageEncoderSettings)
+            {
+                FullDocument = ChangeStreamFullDocumentOption.UpdateLookup
+            };
+            using (var cursor = ExecuteOperation(subject, async))
+            {
+                var filler = new string('x', (numberOfChunks - 1) * 65536);
+                var document = new BsonDocument { { "_id", 1 }, { "filler", filler } };
+                Insert(document);
+
+                ChangeStreamDocument<BsonDocument> changeStreamDocument;
+                do
+                {
+                    if (async)
+                    {
+                        cursor.MoveNextAsync().GetAwaiter().GetResult();
+                    }
+                    else
+                    {
+                        cursor.MoveNext();
+                    }
+
+                    changeStreamDocument = cursor.Current.FirstOrDefault();
+                }
+                while (changeStreamDocument == null);
+
+                changeStreamDocument.FullDocument.Should().Be(document);
+            }
+        }
+
         [SkippableTheory]
         [ParameterAttributeData]
         public void Execute_should_return_expected_results_for_updates(