public void RemoveFlag_ShouldRemoveSingleFlag()
        {
            _status = _status.RemoveFlag(MessageStatus.New);

            Assert.That(_status.HasFlag(MessageStatus.New), Is.False);
            Assert.That(_status.HasFlag(MessageStatus.Sent), Is.False);
            Assert.That(_status.HasFlag(MessageStatus.Received), Is.False);
        }