You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: heartbeat.go
    path of file: ./repos/corteza/extra/server-discovery/vendor/github.com/go-chi/chi/v5/middleware
    
    the code of the file until where you have to start completion: package middleware

import (
	"net/http"
	"strings"
)

// Heartbeat endpoint middleware useful to setting up a path like
// `/ping` that load balancers or uptime testing external services
// can make a request before hitting any routes. It's also convenient
// to place this above ACL middlewares as well.
func Heartbeat(endpoint string) func(http.Handler) http.Handler {
	f := func(h http.Handler) http.
    
func Heartbeat(endpoint string) func(http.Handler) http.Handler {
	f := func(h http.Handler) http.Handler {
		fn := func(w http.ResponseWriter, r *http.Request) {
			if (r.Method == "GET" || r.Method == "HEAD") && strings.EqualFold(r.URL.Path, endpoint) {
				w.Header().Set("Content-Type", "text/plain")
				w.WriteHeader(http.StatusOK)
				w.Write([]byte("."))
				return
			}
			h.ServeHTTP(w, r)
		}
		return http.HandlerFunc(fn)
	}
	return f
}