Function spsv_buffer_size 

pub fn spsv_buffer_size<T: SparseScalar>(
    handle: &Handle,
    op: Op,
    alpha: &T,
    a: &SpMat<'_, T>,
    x: &DnVec<'_, T>,
    y: &DnVec<'_, T>,
    alg: SpSVAlg,
    plan: &SpSVPlan,
) -> Result<usize>