Merge pull request #71 from joho/document_statsd

Add documentation for metrics/statsd

metrics/README.md

@@ -52,3 +52,29 @@ func handleRequest() {
 	// handle request
 }
 ```
+
+A gauge for the number of goroutines currently running, exported via statsd.
+```go
+import (
+	"net"
+	"os"
+	"runtime"
+	"time"
+
+	"github.com/go-kit/kit/metrics/statsd"
+)
+
+func main() {
+	statsdWriter, err := net.Dial("udp", "127.0.0.1:8126")
+	if err != nil {
+		os.Exit(1)
+	}
+
+	reportingDuration := 5 * time.Second
+	goroutines := statsd.NewGauge(statsdWriter, "total_goroutines", reportingDuration)
+	for range time.Tick(reportingDuration) {
+		goroutines.Set(float64(runtime.NumGoroutine()))
+	}
+}
+
+```