Function immutable_seq::node::node3

pub fn node3<T, M>(left: Lazy<Node<T, M>>,
                   middle: Lazy<Node<T, M>>,
                   right: Lazy<Node<T, M>>)
                   -> Lazy<Node<T, M>> where T: Measure<M> + 'static, M: Add<Output=M> + Copy + 'static

Construct a lazy reference to a node with three children