def METHOD_NAME(
    self,
    time_s: float,
    array: np.ndarray,
) -> int | float:
    '''
    Return array shm-buffer index for for epoch time.
    '''
    times = array['time']
    first = np.searchsorted(
        times,
        time_s,
        side='left',
    )
    imx = times.shape[0] - 1
    return min(first, imx)