 }
 
 extension Atomic {
-    #if os(macOS) || os(iOS) || os(tvOS) || os(watchOS)
     @available(iOS 10.0, *)
     @available(macOS 10.12, *)
     @available(tvOS 10.0, *)

final class Atomic<Value> {
    private var _value: Value
    private let lock: NSLocking = {
        #if os(macOS) || os(iOS) || os(tvOS) || os(watchOS)
            if #available(*, iOS 10.0, macOS 10.12, tvOS 10.0, watchOS 3.0) {
                return OSUnfairLock()
            }
        #endif
        return PosixThreadMutex()
    }()
    

            os_unfair_lock_unlock(_lock)
        }
    }
    
    private final class PosixThreadMutex: NSLocking {
        private let _lock = UnsafeMutablePointer<pthread_mutex_t>.allocate(capacity: 1)
