while (curr != null and curr.?.key != null and lessThan(context, curr.?.key.?, key)) {

                while (curr != null and lessThan(context, curr.?.key.?, key)) {

            // const preds = self.allocator.alloc(?*Node, max_level) catch unreachable;
            // @memset(preds, null);
            // defer self.allocator.free(preds);
            // const succs = self.allocator.alloc(?*Node, max_level) catch unreachable;
            // @memset(succs, null);
            // defer self.allocator.free(succs);

                    std.debug.assert(node.nexts.len == rlevel + 1);

                            // If the next is not null, make sure its key is set
                            if (node.nexts[level]) |next_node| {
                                std.debug.assert(next_node.key != null);
                            }
                            // Check if all pred nodes were locked when we inserted this node.

                        }
                    }
                    if (builtin.mode == .Debug) {
                        for (node.nexts) |item| {
                            std.debug.assert(node.nexts.len == rlevel + 1);
                            if (item != null) {
                                std.debug.assert(item.?.key != null);
                                continue;
                            }
                            std.debug.assert(item == null);