enum Change A single change to a collection. Cases case insert Required An insertion. The offset value is the offset of the inserted element in the final state of the collection after the difference is fully applied. A non-nil associatedWith value is the offset of the complementary change. Declaration case insert(offset: Int, element: ChangeElement, associatedWith: Int?) case remove Required A removal. The offset value is the offset of the element to be removed in the original state of the collection. A non-nil associatedWith value is the offset of the complementary change. Declaration case remove(offset: Int, element: ChangeElement, associatedWith: Int?)