that during changing no any other modifications could be made on this item by concurrent threads.
Returns std::pair<bool, bool> where \p first is \p true if operation is successful,
- \p second is \p true if new item has been added or \p false if the item with \p key
- already is in the list.
+ \p second is \p true if new item has been added or \p false if the item with that key
+ already in the list.
@warning See \ref cds_intrusive_item_creating "insert item troubleshooting"
*/