package main import ( "fmt" "net/http" "github.com/julienschmidt/httprouter" ) func main() { router := httprouter.New() router.GET("/user/:username", func(w http.ResponseWriter, r *http.Request, ps httprouter.Params) { fmt.Fprintf(w, "Username is %s", ps.ByName("username")) }) http.ListenAndServe(":8080", router) }In this example, we define a new `httprouter` instance and define a GET route with a URL pattern containing a `username` parameter. When a user makes a request to the URL with a specified `username`, the server extracts the parameter from the URL and sends it as a response to the client. Overall, `github.com.julienschmidt.httprouter.Params` is a powerful package for building efficient and scalable HTTP APIs and web applications using Go. It provides an easy-to-use HTTP request router with support for basic and advanced routing capabilities, as well as middleware and other useful features.