(Changed in version 2.8.0) collect has changed. The previous behavior can be reproduced with toSeq.
(bSONIterator: MonadOps[(String, BSONValue)]).filter(p)
(bSONIterator: MonadOps[(String, BSONValue)]).flatMap(f)
(bSONIterator: MonadOps[(String, BSONValue)]).map(f)
(bSONIterator: MonadOps[(String, BSONValue)]).withFilter(p)