code: func (c *nfsdCollector) updateNFSdReadAheadCacheStats(ch chan<- prometheus.Metric, s *nfs.ReadAheadCache) {
  	ch <- prometheus.MustNewConstMetric(
  		prometheus.NewDesc(
  			prometheus.BuildFQName(namespace, nfsdSubsystem, "read_ahead_cache_size_blocks"),
  			"How large the read ahead cache is in blocks.",
  			nil,
  			nil,
  		),
  		prometheus.GaugeValue,
  		float64(s.CacheSize))
  	ch <- prometheus.MustNewConstMetric(
  		prometheus.NewDesc(
  			prometheus.BuildFQName(namespace, nfsdSubsystem, "read_ahead_cache_not_found_total"),
  			"Total number of NFSd read ahead cache not found.",
  			nil,
  			nil,
  		),
  		prometheus.CounterValue,
  		float64(s.NotFound))
  }
docs: // updateNFSdReadAheadCacheStats collects statistics for the read ahead cache.