small fix

Author: papafe

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

@@ -296,7 +296,6 @@ public IChangeStreamCursor<TResult> Execute(OperationContext operationContext, I
                 initialOperationTime = GetInitialOperationTimeIfRequired(context, cursorBatchInfo);
 
                 var postBatchResumeToken = GetInitialPostBatchResumeTokenIfRequired(cursorBatchInfo);
-                var serializationDomain = _messageEncoderSettings.GetOrDefault<IBsonSerializationDomain>(MessageEncoderSettingsName.SerializationDomain, null);
 
                 return new ChangeStreamCursor<TResult>(
                     cursor,
@@ -309,7 +308,7 @@ public IChangeStreamCursor<TResult> Execute(OperationContext operationContext, I
                     _resumeAfter,
                     _startAtOperationTime,
                     context.Channel.ConnectionDescription.MaxWireVersion,
-                    serializationDomain);
+                    _serializationDomain);
             }
         }
 
@@ -333,7 +332,6 @@ public async Task<IChangeStreamCursor<TResult>> ExecuteAsync(OperationContext op
                 initialOperationTime = GetInitialOperationTimeIfRequired(context, cursorBatchInfo);
 
                 var postBatchResumeToken = GetInitialPostBatchResumeTokenIfRequired(cursorBatchInfo);
-                var serializationDomain = _messageEncoderSettings.GetOrDefault<IBsonSerializationDomain>(MessageEncoderSettingsName.SerializationDomain, null);
 
                 return new ChangeStreamCursor<TResult>(
                     cursor,
@@ -346,7 +344,7 @@ public async Task<IChangeStreamCursor<TResult>> ExecuteAsync(OperationContext op
                     _resumeAfter,
                     _startAtOperationTime,
                     context.Channel.ConnectionDescription.MaxWireVersion,
-                    serializationDomain);
+                    _serializationDomain);
             }
         }