https://github.com/pointcache/Unity3d-Timers

Unity3d-Timers

Timer class with various behaviors

About: Have a system allowing to easily create and extend complex timer behaviors.

Usage:

//Start simple repeater
Timer.Repeater(5f, () => Debug.Log("Repeater test"));
//Start countdown and call Draw in 2.5 seconds
Timer.Countdown(2.5f, Draw);

Concept: A manager class pools and constructs new timers, timer store up to 4 handlers, and arbitrarely raise events in concrete implementation.

private class CountdownBehavior : TimerBehaviorBase, ITimerBehavior
{
    float exitTime;
    public void Initialize()
    {
        exitTime = f1;
    }

    public void Update(float deltaTime)
    {
        TimePassed += deltaTime;
        TotalTimeActive += deltaTime;

        if (TimePassed > exitTime)
        {
            Completed = true;
            c1();
        }
    }
}

Countdown inherits TimerBehaviorBase and implements ITimerBehavior. On top of that only concrete behavior in implemented that uses data and callbacks provided in constructor:

public static Timer Countdown(float exitTime, Action callback)
{
    Timer timer = TimerManager.getTimer();
    timer.SetBehavior<CountdownBehavior>();
    timer.behaviorBase
        .SetFloats(exitTime, 0, 0, 0)
        .SetCallbacks(callback, null, null, null);
    timer.behavior.Initialize();
    return timer;
}

as you can see you can set 4 floats, and 4 callbacks and use them in your implementation of behavior as you like. Examples 

For concrete real example look at Ability class, it implements typical game ability, with cooldown.