ASStackLayoutSpec utilizes multiple threads if it runs on main (#3116)
ASStackLayoutSpec utilizes multiple threads if it runs on main (#3116)


maicki/AsyncDisplayKit,maicki/AsyncDisplayKit,flovouin/AsyncDisplayKit,maicki/AsyncDisplayKit,lappp9/AsyncDisplayKit,lappp9/AsyncDisplayKit,maicki/AsyncDisplayKit,lappp9/AsyncDisplayKit,lappp9/AsyncDisplayKit,maicki/AsyncDisplayKit,flovouin/AsyncDisplayKit,flovouin/AsyncDisplayKit,flovouin/AsyncDisplayKit,flovouin/AsyncDisplayKit