Time.realTimeSinceStartup in Unity

Notes:

Time.realtimeSinceStartup in Unity
- returns the real time passed in seconds; since the game started

Time.realtimeSinceStartup = Total game play time + Total game pause time

Note: is not affected by Time.timeScale
i.e. even if the game is paused behind the scene it keeps on updating and does not scale or descale according to Time.timeScale value.

Application:
If you want to perform some actions with respect to time even if the game is paused use Time.realtimeSinceStartup.

Example Code:

void Start ()
{
Debug.Log ((int)Time.realtimeSinceStartup);
}

void Update ()
{
Debug.Log ((int)Time.realtimeSinceStartup);
}

void OnApplicationQuit()
{
Debug.Log ((int)Time.realtimeSinceStartup);
}