是否有最佳实践来实现静态函数，该函数为同时访问提供了独特的价值

A static function retUnique() returns a unique value. My question is that if there are many users who are using the same function at a given point of time, what happens? Is there a best practice to make sure that each users accessing this static function simultaneously get a unique value and also do not face threading issues. returns a unique