code: func (mx *Mux) With(middlewares ...func(http.Handler) http.Handler) Router {
  	// Similarly as in handle(), we must build the mux handler once further
  	// middleware registration isn't allowed for this stack, like now.
  	if !mx.inline && mx.handler == nil {
  		mx.buildRouteHandler()
  	}
  
  	// Copy middlewares from parent inline muxs
  	var mws Middlewares
  	if mx.inline {
  		mws = make(Middlewares, len(mx.middlewares))
  		copy(mws, mx.middlewares)
  	}
  	mws = append(mws, middlewares...)
  
  	im := &Mux{pool: mx.pool, inline: true, parent: mx, tree: mx.tree, middlewares: mws}
  
  	return im
  }
docs: // With adds inline middlewares for an endpoint handler.