     }
     
     private func active(execute body: @convention(block) () -> ()) {
-        if #available(OSX 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *), OS_ACTIVITY_OBJECT_API != 0 {
+        if #available(OSX 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *) {
             _os_activity_apply(opaque, body)
         } else {
             let context = opaque as! LegacyActivityContext

        
        /// Pops activity state to `self`.
        public mutating func leave() {
            if #available(OSX 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *), OS_ACTIVITY_OBJECT_API != 0 {
                _os_activity_scope_leave(&state)
            } else {
                UnsafeRawPointer(bitPattern: Int(state.opaque.0)).map(Unmanaged<AnyObject>.fromOpaque)?.release()

    ///
    public func enter() -> Scope {
        var scope = Scope()
        if #available(OSX 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *) {
            _os_activity_scope_enter(opaque, &scope.state)
        } else {
            let context = opaque as! LegacyActivityContext
