Use the @synchronized to access NSURLCache to fix the potential thread-safe problem, also fix that we always use shared cache but not follow session's configuration
Use the @synchronized to access NSURLCache to fix the potential thread-safe problem, also fix that we always use shared cache but not follow session's configuration

dreampiggy/SDWebImage,rs/SDWebImage,iheartradio/SDWebImage,awkward/SDWebImage,tualatrix/SDWebImage,zhang-yawei/SDWebImage,dreampiggy/SDWebImage,dreampiggy/SDWebImage,smule/SDWebImage,awkward/SDWebImage,Insfgg99x/SDWebImage,awkward/SDWebImage