         self.opaque = description.withUTF8Buffer { (buf: UnsafeBufferPointer<UInt8>) -> AnyObject in
             let str = buf.baseAddress!.withMemoryRebound(to: Int8.self, capacity: 8, { $0 })
             let flags = os_activity_flag_t(rawValue: options.rawValue)
-            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, *) {
                 return _os_activity_create(dso, str, OS_ACTIVITY_CURRENT, flags)
             } else {
                 return LegacyActivityContext(dsoHandle: dso, description: str, flags: flags)

    ///
    public func enter() -> Scope {
        var scope = Scope()
        if #available(OSX 10.12, iOS 10.0, watchOS 3.0, tvOS 10.0, *), OS_ACTIVITY_OBJECT_API != 0 {
            _os_activity_scope_enter(opaque, &scope.state)
        } else {
            let context = opaque as! LegacyActivityContext

    }
    
    private func active(execute body: @convention(block) () -> Void) {
        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
