IMAP IDLE似乎不适用于iCloud电子邮件和S22.IMAP

Question

我正在使用S22.IMAP实现显示here的示例，特别是NewMessage事件。

我正在从我的Gmail帐户向我的iCloud发送测试电子邮件，但事件未触发。我将其撤消并发送到我的Gmail，该事件被解雇了。 iCloud实际上不支持IMAP IDLE吗？它没有抛出异常，说它没有或是否有一些特殊的事情要让iCloud推送到您的应用程序？

    public EmailInstance(String email, SupportedMailTypes type)
    {
        _emailAddress = email;
        _mailType = type;
        InitializeEmail();
    }

    private void InitializeEmail()
    {
        if (_mailType == SupportedMailTypes.Gmail)
        {
            _client = new ImapClient(GMAIL_SERVER, PORT, _emailAddress, PASSWORD, AuthMethod.Login, true);                          
        }
        else if (_mailType == SupportedMailTypes.iCloud)
        {
            _client = new ImapClient(ICLOUD_SERVER, PORT, _emailAddress, PASSWORD, AuthMethod.Login, true);
        }

        // Download mail messages from the default mailbox.
        NewEmailCount = GetMessageCount();

        // Check that IDLE is supported by the server
        if (_client.Supports("IDLE") == false)
        {
            throw new Exception("Server does not support IDLE.");
        }

        _client.IdleError += OnIdleError;
        _client.NewMessage += OnNewMessage;
        _client.MessageDeleted += OnMessageDeleted;
    }

    /// <summary>
    /// If idling throws an error.
    /// </summary>
    private void OnIdleError(object sender, IdleErrorEventArgs e)
    {
        throw new Exception(e.Exception.Message);
    }

    /// <summary>
    /// What to do when the client receives a new message.
    /// </summary>
    private void OnNewMessage(object sender, IdleMessageEventArgs e)
    {
        NewEmailCount = GetMessageCount(); 
        var header = _client.GetMessage(e.MessageUID, FetchOptions.HeadersOnly, false);
    }

    private void OnMessageDeleted(object sender, IdleMessageEventArgs e)
    {
        NewEmailCount = GetMessageCount();
    }

    /// <summary>
    /// Returns the message count
    /// </summary>
    private int GetMessageCount()
    {
        var uids = _client.Search(SearchCondition.Unseen());                    
        return _client.GetMessages(uids, FetchOptions.HeadersOnly, false).Count();
    }