private void _GenPair()
    {
        Transform2[] __copy = new Transform2[_raycastPairsTrans.GetLength(0) + 1];
        _raycastPairsTrans.CopyTo(__copy, 0);
        _raycastPairsTrans = new Transform2[_raycastPairsTrans.GetLength(0) + 1];
        __copy.CopyTo(_raycastPairsTrans, 0);

        int     i         = _raycastPairsTrans.GetLength(0) - 1;
        Vector2 __leftPos = new Vector2(
            transform.position.x - 4,
            transform.position.y - 1
            );

        Vector2 __rightPos = new Vector2(
            transform.position.x + 4,
            transform.position.y - 1
            );

        _raycastPairsTrans[i].firstTrans  = Instantiate(_pairPrefab, __leftPos, Quaternion.identity).GetComponent <Transform>();
        _raycastPairsTrans[i].secondTrans = Instantiate(_pairPrefab, __rightPos, Quaternion.identity).GetComponent <Transform>();

        _raycastPairsTrans[i].firstTrans.name = "Pair_s left end " +
                                                i;
        _raycastPairsTrans[i].secondTrans.name = "Pair_s right end " +
                                                 i;

        _raycastPairsTrans[i].firstTrans.parent  = transform;
        _raycastPairsTrans[i].secondTrans.parent = transform;
    }