internal static void _scheduleImmediate(ZoneCallback callback)
{
Isolate.ensureExists();
GCHandle callabackHandle = GCHandle.Alloc(callback);
UIMonoState_scheduleMicrotask(_scheduleMicrotask, (IntPtr)callabackHandle);
}
void _enqueue()
{
Isolate.ensureExists();
GCHandle callbackHandle = GCHandle.Alloc(this);
UIMonoState_postTaskForTime(_postTaskForTime, (IntPtr)callbackHandle, _wakeupTime * MILLI_TO_NANO);
}