Convert remaining collectors to use ConstMetrics

collector/collector.go

@@ -32,3 +32,12 @@ type Collector interface {
 	// Get new metrics and expose them via prometheus registry.
 	Update(ch chan<- prometheus.Metric) (err error)
 }
+
+type typedDesc struct {
+	desc      *prometheus.Desc
+	valueType prometheus.ValueType
+}
+
+func (d *typedDesc) mustNewConstMetric(value float64, labels ...string) prometheus.Metric {
+	return prometheus.MustNewConstMetric(d.desc, d.valueType, value, labels...)
+}