code: public IEdge connect(INode source, INode target, VFBondMatcher matcher) {
          NodeBuilder sourceImpl = (NodeBuilder) source;
          NodeBuilder targetImpl = (NodeBuilder) target;
          EdgeBuilder edge = new EdgeBuilder(sourceImpl, targetImpl, matcher);
  
          sourceImpl.addNeighbor(targetImpl);
          targetImpl.addNeighbor(sourceImpl);
  
          sourceImpl.addEdge(edge);
          targetImpl.addEdge(edge);
  
          edgesList.add(edge);
          return edge;
      }
docs: Construct and return an edge for a given query and target node
  @param source
  @param target
  @param matcher
  @return connected edges