code: func Wrap(handler http.Handler) http.Handler {
  	mux := http.NewServeMux()
  	mux.HandleFunc("/debug/pprof/", pprof.Index)
  	mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
  	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
  	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
  	mux.HandleFunc("/debug/pprof/block", blockHandler)
  	mux.HandleFunc("/debug/vars", expvarHandler)
  	mux.HandleFunc("/debug/gc", performGC)
  	mux.Handle("/", handler)
  	return mux
  }
docs: // Wrap returns a handler which adds the following URLs as special cases:
  //
  //     /debug/pprof/        -- an HTML index of pprof endpoints
  //     /debug/pprof/cmdline -- the running process's command line
  //     /debug/pprof/profile -- pprof profiling endpoint
  //     /debug/pprof/symbol  -- pprof debugging symbols
  //     /debug/vars          -- JSON-formatted expvars