ChangeStream Publisher's cursor does not closed after .cancel()

We start a Change Stream Publisher on a collection.

Do not execute any operation on this collection at that time.

The AsyncChangeStreamBatchCursor would call getMore command every second.

Now we invoke subscription.cancel() method.

The AsyncChangeStreamBatchCursor should be closed, but it doesn't.

The property isOperationInProgress == true , isClosePending == true and the Cursor continue in getMore loop, never closed.