Function rs_graph::maxflow::edmondskarp

pub fn edmondskarp<'a, G, F, Us>(
    g: &'a G, 
    src: G::Node, 
    snk: G::Node, 
    upper: Us
) -> (F, EdgeVec<&'a G, F>, Vec<G::Node>) where
    G: IndexDigraph<'a>,
    F: 'a + NumAssign + Ord + Copy,
    Us: Fn(G::Edge) -> F, 

Solve the maxflow problem using the algorithm of Edmonds-Karp.