add groups feature

lib/util/timeutil.js

@@ -0,0 +1,22 @@
+/**
+* Copyright © 2019 code initially contributed by Orange SA, authors: Denis Barbaron - Licensed under the Apache license 2.0
+**/
+
+const timeutil = Object.create(null)
+
+timeutil.now = function(unit) {
+  const hrTime = process.hrtime()
+
+  switch (unit) {
+    case 'milli':
+      return hrTime[0] * 1000 + hrTime[1] / 1000000
+    case 'micro':
+      return hrTime[0] * 1000000 + hrTime[1] / 1000
+    case 'nano':
+      return hrTime[0] * 1000000000 + hrTime[1]
+    default:
+      return hrTime[0] * 1000000000 + hrTime[1]
+  }
+}
+
+module.exports = timeutil