Time the stress test

Common/TimeUtil.h

@@ -7,3 +7,17 @@ double time_now_d();
 void sleep_ms(int ms);
 
 void GetTimeFormatted(char formattedTime[13]);
+
+// Rust-style Instant for clear and easy timing.
+class Instant {
+public:
+	static Instant Now() {
+		return Instant(time_now_d());
+	}
+	double Elapsed() const {
+		return time_now_d() - instantTime_;
+	}
+private:
+	explicit Instant(double initTime) : instantTime_(initTime) {}
+	double instantTime_;
+};