find downslope coordinate for Dinf of TauDEM
        Args:
            dinfdir_value: dinf direction value
            i: current row
            j: current col

        Returns:
            downstream (row, col)s

def downstream_index_dinf(dinfdir_value, i, j):
        """find downslope coordinate for Dinf of TauDEM
        Args:
            dinfdir_value: dinf direction value
            i: current row
            j: current col

        Returns:
            downstream (row, col)s
        """
        down_dirs = DinfUtil.dinf_downslope_direction(dinfdir_value)
        down_coors = []
        for dir_code in down_dirs:
            row, col = D8Util.downstream_index(dir_code, i, j)
            down_coors.append([row, col])
        return down_coors