Function reduce_with 

pub fn reduce_with<F>(
    core: &Core,
    binding: &Arc<dyn OperatorBinding>,
    source: NodeId,
    fold: F,
    seed: HandleId,
    opts: OperatorOpts,
) -> OperatorRegistration
where
    F: Fn(HandleId, HandleId) -> HandleId + Send + Sync + 'static,

reduce with explicit OperatorOpts.