Move edge_count() in method order

src/models/append_graph.rs

@@ -80,10 +80,6 @@ impl GraphTopology for AppendGraph {
         self.vertices.len()
     }
 
-    fn edge_count(&self) -> usize {
-        self.incidences.len() / 2
-    }
-
     fn vertex_capacity(&self) -> usize {
         self.vertices.len()
     }
@@ -92,6 +88,10 @@ impl GraphTopology for AppendGraph {
         VertexMap::new(default, |v| v.0, self.vertex_capacity())
     }
 
+    fn edge_count(&self) -> usize {
+        self.incidences.len() / 2
+    }
+
     fn degree(&self, v: Self::Vertex) -> usize {
         self.vertices[v.0].incidence_count
     }