gistfile1.txt

 // map<string, set<string>>
        public void MultiDeleteAll(Slice key)
        {
            State.IsModified = true;
            var page = FindPageFor(key, out _);
            if (page == null || page.LastMatch != 0)
            {
                return; //nothing to delete - key not found
            }

            page = ModifyPage(page);

            var item = page.GetNode(page.LastSearchPosition);

            if (item->Flags == TreeNodeFlags.MultiValuePageRef) //multi-value tree exists
            {
                var tree = OpenMultiValueTree(key, item);
                _tx.TryRemoveMultiValueTree(this, key);

                foreach (long treePage in tree.AllPages())
                {
                    if (_newPageAllocator != null)
                    {
                        if (IsIndexTree == false)
                            ThrowAttemptToFreePageToNewPageAllocator(Name, treePage);

                        _newPageAllocator.FreePage(treePage);
                    }
                    else
                    {
                        if (IsIndexTree)
                            ThrowAttemptToFreeIndexPageToFreeSpaceHandling(Name, treePage);

                        _llt.FreePage(treePage);
                    }
                }

                Delete(key);
            }

            Delete(key);
        }