Currently if applications want to have continued access to ChangeStream.Current after calling Next/TryNext, they have to make a copy of it. This is every inefficient for applications that usually get large change events, and continued access for change streams is very common, for example putting the current event to a queue for async processing. It seems that the reason we have to do this is because the ChangeStream.Current slice can be overwritten, so this ticket is to improve the implementation to avoid applications doing extra copy.