+ if(block)
+ tick();
+ else
+ tick(zero);
+}
+
+void Timer::tick()
+{
+ do_tick(-sec);
+}
+
+void Timer::tick(const TimeDelta &timeout)
+{
+ do_tick(timeout);
+}
+
+void Timer::do_tick(const TimeDelta &timeout)
+{
+ TimeStamp deadline;
+ if(timeout>=zero)
+ deadline = now()+timeout;
+