@interface RCUnfairLock : NSObject @property (nonatomic) struct os_unfair_lock_s { unsigned int _os_unfair_lock_opaque; } unfairLock; @property (nonatomic) unsigned int unfairLockOptions; - (id)init; - (void)lock; - (void)performWithLockSync:(id /* block */)a0; - (void)unlock; - (id)initWithOptions:(long long)a0; @end