SendMailAsync with cancellation token

SmtpClientWrapper.cs

public class SmtpClientWrapper : IDisposable  
{
    private SmtpClient _smtpClient;

    public SmtpClientWrapper(SmtpClient smtpClient)
    {
        this._smtpClient = smtpClient;
    }

    public async Task SendMailAsync(MailMessage message, CancellationToken ct)
    {
        using (ct.Register(_smtpClient.SendAsyncCancel))
        {
            await _smtpClient.SendMailAsync(message);
        }
    }

    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }

    protected virtual void Dispose(bool p)
    {
        if (_smtpClient != null)
        {
            _smtpClient.Dispose();
            _smtpClient = null;
        }
    }

}