code: func UninstrumentedHandler() http.Handler {
  	return http.HandlerFunc(func(rsp http.ResponseWriter, req *http.Request) {
  		mfs, err := DefaultGatherer.Gather()
  		if err != nil {
  			httpError(rsp, err)
  			return
  		}
  
  		contentType := expfmt.Negotiate(req.Header)
  		header := rsp.Header()
  		header.Set(contentTypeHeader, string(contentType))
  
  		w := io.Writer(rsp)
  		if gzipAccepted(req.Header) {
  			header.Set(contentEncodingHeader, "gzip")
  			gz := gzipPool.Get().(*gzip.Writer)
  			defer gzipPool.Put(gz)
  
  			gz.Reset(w)
  			defer gz.Close()
  
  			w = gz
  		}
  
  		enc := expfmt.NewEncoder(w, contentType)
  
  		for _, mf := range mfs {
  			if err := enc.Encode(mf); err != nil {
  				httpError(rsp, err)
  				return
  			}
  		}
  	})
  }
docs: // UninstrumentedHandler returns an HTTP handler for the DefaultGatherer.
  //
  // Deprecated: Use promhttp.HandlerFor(DefaultGatherer, promhttp.HandlerOpts{})
  // instead. See there for further documentation.