code: func Graphite(r Registry, d time.Duration, prefix string, addr *net.TCPAddr) {
  	GraphiteWithConfig(GraphiteConfig{
  		Addr:          addr,
  		Registry:      r,
  		FlushInterval: d,
  		DurationUnit:  time.Nanosecond,
  		Prefix:        prefix,
  		Percentiles:   []float64{0.5, 0.75, 0.95, 0.99, 0.999},
  	})
  }
docs: // Graphite is a blocking exporter function which reports metrics in r
  // to a graphite server located at addr, flushing them every d duration
  // and prepending metric names with prefix.