driver-core/src/main/com/mongodb/internal/connection/ConcurrentLinkedDeque.java
Node<E> forward() {
            Node<E> f = successor();
            return (f == null || f.isSpecial()) ? null : f;
        }
Node<E> forward() {
            Node<E> f = successor();
            return (f == null || f.isSpecial()) ? null : f;
        }
Returns the next node containing a nondeleted user element.
Use for forward list traversal.

@return successor, or null if no such