Android Double Click Escape to Exit

public GameObject quitobject;
private bool clickedBefore = false;

void Update()
{
    //Check input for the first time
    if (Input.GetKeyDown(KeyCode.Escape) && !clickedBefore)
    {
        Debug.Log("Back Button pressed for the first time");
        //Set to false so that this input is not checked again. It will be checked in the coroutine function instead
        clickedBefore = true;

        //Activate Quit Object
        quitobject.SetActive(true);

        //Start quit timer
        StartCoroutine(quitingTimer());
    }
}

IEnumerator quitingTimer()
{
    //Wait for a frame so that Input.GetKeyDown is no longer true
    yield return null;

    //3 seconds timer
    const float timerTime = 3f;
    float counter = 0;

    while (counter < timerTime)
    {
        //Increment counter while it is < timer time(3)
        counter += Time.deltaTime;

        //Check if Input is pressed again while timer is running then quit/exit if is
        if (Input.GetKeyDown(KeyCode.Escape))
        {
            Debug.Log("Back Button pressed for the second time. EXITING.....");
            Quit();
        }

        //Wait for a frame so that Unity does not freeze
        yield return null;
    }

    Debug.Log("Timer finished...Back Button was NOT pressed for the second time within: '" + timerTime + "' seconds");

    //Timer has finished and NO QUIT(NO second press) so deactivate
    quitobject.SetActive(false);
    //Reset clickedBefore so that Input can be checked again in the Update function
    clickedBefore = false;
}

void Quit()
{
    #if UNITY_EDITOR
    UnityEditor.EditorApplication.isPlaying = false;
    #else
    //Application.Quit();
    System.Diagnostics.Process.GetCurrentProcess().Kill();
    #endif
}
//Wait for a frame so that Unity does not freeze
        yield return null;
    }

    Debug.Log("Timer finished...Back Button was NOT pressed for the second time within: '" + timerTime + "' seconds");

    //Timer has finished and NO QUIT(NO second press) so deactivate
    quitobject.SetActive(false);
    //Reset clickedBefore so that Input can be checked again in the Update function
    clickedBefore = false;
}

void Quit()
{
    #if UNITY_EDITOR
    UnityEditor.EditorApplication.isPlaying = false;
    #else
    //Application.Quit();
    System.Diagnostics.Process.GetCurrentProcess().Kill();
    #endif
}