Complexity: length + m, where m is the length of stuff.
Array.insertBefore
size_t insertBefore(Stuff)(Range r, Stuff stuff)Inserts stuff before, after, or instead range r, which must be a valid range previously extracted from this array. stuff can be a value convertible to bool or a range of objects convertible to bool. Both stable and non-stable version behave the same and guarantee that ranges iterating over the array are never invalidated.
Returns
The number of values inserted.