code: private void addInternal(int i, Composite start, Composite end, long markedAt, int delTime)
      {
          assert i >= 0;
  
          if (size == capacity())
              growToFree(i);
          else if (i < size)
              moveElements(i);
  
          setInternal(i, start, end, markedAt, delTime);
          size++;
      }
docs: /*
  Adds the new tombstone at index i, growing and/or moving elements to make room for it.