code: func ReportRuntimeMetrics() {
  	var memstats runtime.MemStats
  	runtime.ReadMemStats(&memstats)
  	numGoroutines := runtime.NumGoroutine()
  
  	r := map[string]float64{
  		"goroutine":                     float64(numGoroutines),
  		"runtime.MemStats.Alloc":        float64(memstats.Alloc),
  		"runtime.MemStats.Frees":        float64(memstats.Frees),
  		"runtime.MemStats.HeapAlloc":    float64(memstats.HeapAlloc),
  		"runtime.MemStats.HeapIdle":     float64(memstats.HeapIdle),
  		"runtime.MemStats.HeapObjects":  float64(memstats.HeapObjects),
  		"runtime.MemStats.HeapReleased": float64(memstats.HeapReleased),
  		"runtime.MemStats.HeapSys":      float64(memstats.HeapSys),
  		"runtime.MemStats.LastGC":       float64(memstats.LastGC),
  		"runtime.MemStats.Lookups":      float64(memstats.Lookups),
  		"runtime.MemStats.Mallocs":      float64(memstats.Mallocs),
  		"runtime.MemStats.MCacheInuse":  float64(memstats.MCacheInuse),
  		"runtime.MemStats.MCacheSys":    float64(memstats.MCacheSys),
  		"runtime.MemStats.MSpanInuse":   float64(memstats.MSpanInuse),
  		"runtime.MemStats.MSpanSys":     float64(memstats.MSpanSys),
  		"runtime.MemStats.NextGC":       float64(memstats.NextGC),
  		"runtime.MemStats.NumGC":        float64(memstats.NumGC),
  		"runtime.MemStats.PauseTotalMs": float64(memstats.PauseTotalNs) / float64(time.Millisecond),
  		"runtime.MemStats.StackInuse":   float64(memstats.StackInuse),
  	}
  
  	for name, value := range r {
  		Gauge(name, value, nil, 1.0)
  	}
  }
docs: // Samples and reports current runtime status once.