code: func RegisterMetrics() {
  	registerMetricsOnce.Do(func() {
  		prometheus.MustRegister(SyncProxyRulesLatency)
  		prometheus.MustRegister(DeprecatedSyncProxyRulesLatency)
  		prometheus.MustRegister(NetworkProgrammingLatency)
  	})
  }
docs: // RegisterMetrics registers kube-proxy metrics.