dispatch_source_set_timer(timerSource, dispatch_time(DISPATCH_TIME_NOW, nanos), nanos, leeway);
dispatch_source_set_event_handler(timerSource, ^{
__CFMachPortChecker(true);
});
dispatch_resume(timerSource);
dispatch_source_set_timer(timerSource, dispatch_time(DISPATCH_TIME_NOW, nanos), nanos, leeway);
dispatch_source_set_event_handler(timerSource, ^{
__CFMachPortChecker(true);
});
dispatch_resume(timerSource);