exchange: Extend Transport Queue metrics (#1749)

Signed-off-by: Jan-Otto Kröpke <mail@jkroepke.de>

internal/collector/exchange/exchange_availability_service.go

@@ -7,11 +7,14 @@ import (
 	"fmt"
 
 	"github.com/prometheus-community/windows_exporter/internal/perfdata"
+	"github.com/prometheus-community/windows_exporter/internal/types"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
 func (c *Collector) buildAvailabilityService() error {
-	counters := []string{}
+	counters := []string{
+		requestsPerSec,
+	}
 
 	var err error
 
@@ -20,6 +23,13 @@ func (c *Collector) buildAvailabilityService() error {
 		return fmt.Errorf("failed to create MSExchange Availability Service collector: %w", err)
 	}
 
+	c.availabilityRequestsSec = prometheus.NewDesc(
+		prometheus.BuildFQName(types.Namespace, Name, "avail_service_requests_per_sec"),
+		"Number of requests serviced per second",
+		nil,
+		nil,
+	)
+
 	return nil
 }