Swift 插件com.apple.share.Mail.compose无效（Cocoa NsharingServiceNameComposeEmail）

在我的Cocoa应用程序中，我有一个用于发送电子邮件的按钮：

@IBAction func emailFeedBack(sender: NSButton) {
    sender.enabled = false

    //mail composition
    let subject = "[Feedback]"
    let body = "\n\n\nFeedback From my app:\n"
    let service = NSSharingService(named: NSSharingServiceNameComposeEmail)
    service?.delegate = self
    service?.recipients = ["myMail@mail.com"]
    service?.subject = subject
    let shareItems = [body] as NSArray
    service?.performWithItems(shareItems as [AnyObject])

    //activate the button after 1 sec
    let delayTime = (Int64(NSEC_PER_SEC) * 1)
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, delayTime),
                   dispatch_get_main_queue(), { () -> Void in
                    sender.enabled = true
    })
}

它可以正常工作并按预期启动邮件应用程序。但是，我在调试控制台上收到以下消息：

插件com.apple.share.Mail.compose无效

---

有人知道如何解决这个问题吗？

我对obj-c项目也有同样的问题。我认为这并不重要，因为一切都正常。我对obj-c项目也有同样的问题。我认为这并不重要，因为一切都正常。