docs: protected void beforeInsertDummies(int index, int length) {
  	if (index > size || index < 0) 
  		throw new IndexOutOfBoundsException("Index: "+index+", Size: "+size);
  	if (length > 0) {
  		ensureCapacity(size + length);
  	    System.arraycopy(elements, index, elements, index + length, size-index);
  		size += length;
  	}
  }