void OpenStartNode()
    {
        AStarEightDirectionsHeapNode startNode = GetNode(_startPosition);

        startNode.Open(_endPosition);

        _openedList.Set(startNode);
    }
    void DoOpenNode(AStarEightDirectionsHeapNode currentNode, AStarEightDirectionsHeapNode openNode)
    {
        openNode.Open(currentNode, _endPosition);

        _openedList.Set(openNode);
    }