Function nd_iter::iter_3d

pub fn iter_3d<A, B, C, AIter, BIter, CIter>(
    a_iter: AIter, 
    b_iter: BIter, 
    c_iter: CIter
) -> IteratorContainer3d<A, B, C, AIter, BIter, CIter> where
    A: Clone,
    B: Clone,
    BIter: Iterator<Item = B> + Clone,
    CIter: Iterator<Item = C> + Clone,