code: func NewRouter(backends ...Backend) router.Router {
  	r := &grpcRouter{
  		h2Server:   &http2.Server{},
  		grpcServer: grpc.NewServer(),
  	}
  	for _, b := range backends {
  		b.RegisterGRPC(r.grpcServer)
  	}
  	r.initRoutes()
  	return r
  }
docs: // NewRouter initializes a new grpc http router