Function connected_components 

pub fn connected_components<V>(
    q: &GraphQuery<V>,
    weight: &TraversalWeight<V>,
) -> Vec<Vec<Pattern<V>>>
where
    V: GraphValue + Clone,
    V::Id: Clone + Eq + Hash + Ord,

Partition the graph into connected components.

Returns a Vec of Vecs; each inner Vec is one component. Uses BFS internally.