code: func (r *Router) Static(path string, root http.Dir, handlers ...HandlerFunc) {
  	path = r.path(path)
  	fileServer := http.StripPrefix(path, http.FileServer(root))
  
  	handlers = append(handlers, func(c *C) {
  		fileServer.ServeHTTP(c.Writer, c.Request)
  	})
  
  	r.ace.httprouter.Handle("GET", r.staticPath(path), func(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
  		c := r.ace.createContext(w, req)
  		c.handlers = handlers
  		c.Next()
  		r.ace.pool.Put(c)
  	})
  }
docs: //Static server static file
  //path is url path
  //root is root directory