add minutes, add hours, add seconds

[Gameralva]

first of all, a congratulation for the work you did when programming this library. :)

if I have a countdown configured, like this:
tDown.setCounter(0, 30, 0, tDown.COUNT_DOWN, tDownComplete)

how could I add more minutes or hours or seconds, at any time once the countdown started, without stopping or pausing or resetting, the countdown will configure it in 30 minutes, suppose that a few minutes have already passed, and at this moment the countdown is like this:
00:13:45

and I want to add 10 minutes, without stopping or pausing or resetting the countdown, and continue like this:
00:23:45

how would I add those minutes?

in advance, I appreciate your attention.

[Gameralva]

Sorry for this question, I will close it, I see that a similar question was already answered here, thanks anyway.