code: func (f DebugFlags) Install(c *mux.PathRecorderMux, flag string, handler func(http.ResponseWriter, *http.Request)) {
  	c.UnlistedHandle("/debug/flags", http.HandlerFunc(f.Index))
  	c.UnlistedHandlePrefix("/debug/flags/", http.HandlerFunc(f.Index))
  
  	url := path.Join("/debug/flags", flag)
  	c.UnlistedHandleFunc(url, handler)
  
  	f.addFlag(flag)
  }
docs: // Install registers the APIServer's flags handler.