Interface for the JXIdleTask class
Idle tasks are performed when there are no other important events
to process. If an idle task needs to be performed at fixed intervals,
it can change the value of *maxSleepTime to the longest interval in
milliseconds that it is willing to wait. The system will then try to
call it again within this time interval. There are no guarantees,
however. It could be called again much sooner or much later.
Remember that your program will be a CPU hog if you set *maxSleepTime
to a very small value. Executing 10 times per second is probably
a reasonable limit. (*maxSleepTime = 100)
maxSleepTime is passed in as a pointer so tasks that don't care about
the time interval can ignore it.
delta indicates the amount of time in milliseconds that has elapsed
since the last call. This can be used to ensure that a task is not
performed too often.
Since most tasks will run at regular intervals, we provide
Ready() to handle this case. The constructor asks for the time
between runs, and Ready() returns true whenever the elapsed time
exceeds the period. It also sets maxSleepTime to the period,
for convenience.
If your task does not operate with a constant period, then simply
pass in zero for the period.
