def METHOD_NAME(
    xs: np.ndarray,
    ys: np.ndarray,
    frames: int,
    # TODO: using this approach, having the ``.zeros()`` alloc lines
    # below in pure python, there were segs faults and alloc crashes..
    # we might need to see how it behaves with shm arrays and consider
    # allocating them once at startup?
    # pre-alloc array of x indices mapping to the start
    # of each window used for downsampling in y.
    # i_win: np.ndarray,
    # pre-alloc array of output downsampled y values
    # y_out: np.ndarray,
    x_start: int,
    step: float,