In reply to dave_59:
Hi, Dave, thanks so much for your anwser, the only thing confused me is that you said “Class methods can only be declared with an automatic lifetime” ? It appears to me that we could use “static” in left to declare a function/task, which means we create a static function/task for this class, is that right ? So why “Class methods can only be declared with an automatic lifetime” ? Is that because " In later revision of SV, you are no longer even allowed to specify a ‘static’ lifetime for a class method." ?
Thanks