How to make a timer with dynamic time on Xamarin cross platform?

Question

C++ / C#

Made a timer

TimeSpan interval= new TimeSpan(0, 0, 0, 0, 700);
Device.StartTimer(interval, () =>
{
        interval=TimeSpan.FromMilliseconds(interval.Milliseconds - 10);
}

but when executed, the value gets smaller and the timer itself runs at the initial interval.

Answer 1

Probably, it is necessary not to write complete nonsense.
Interval is a local copy on the stack, not what you need.