code: public static Runnable onSchedule(Runnable runnable) {
  		Function<Runnable, Runnable> hook = onScheduleHook;
  		if (hook != null) {
  			return hook.apply(runnable);
  		}
  		else {
  			return runnable;
  		}
  	}
docs: Applies the hooks registered with {@link Schedulers#onScheduleHook(String, Function)}.
  
  @param runnable a {@link Runnable} submitted to a {@link Scheduler}
  @return decorated {@link Runnable} if any hook is registered, the original otherwise.