Time is user to call functions in loop at a defined rate.
Loop time can be changed dynamically, it is readjusted on the next timer call.
Start timer, is the timer is already running dosen't do anything.
The callback is called right after starting the timer.
Indicates if the timer is currently running, it is set to true on start and reset to false on stop.
ID of the currently waiting timeout clock. Used to cancel the already request execution of the next clock tick.