Remove dispatch_queue_async_safe && optimize dispatch_main_async_safe
Remove dispatch_queue_async_safe && optimize dispatch_main_async_safe

awkward/SDWebImage,awkward/SDWebImage,dreampiggy/SDWebImage,dreampiggy/SDWebImage,tualatrix/SDWebImage,rs/SDWebImage,dreampiggy/SDWebImage,awkward/SDWebImage,zhang-yawei/SDWebImage