framework database配置auto_timestamp和datetime

database文件配置

'auto_timestamp'  => true,

    // 时间字段取出后的默认时间格式
    'datetime_format' => 'Y-m-d H:i:s',

    // 时间字段配置 配置格式：create_time,update_time
    'datetime_field'  => 'created_at,updated_at',

模型文件必需配置$createTime、$updateTime或者$autoWriteTimestamp，或者将ModelService设置autoWriteTimestamp的代码调至设置时间字段代码的后面，就能生效。不生效

class Model extends \think\Model
{
}

生效

class Model extends \think\Model
{
      protected $autoWriteTimestamp = true;
}

生效

class Model extends \think\Model
{
     protected $createTime = 'created_at';
     protected $updateTime = 'updated_at';
}

生效

class ModelService extends Service
{
    public function boot()
    {
		//
        Model::setDb($this->app->db);
        Model::setEvent($this->app->event);
        Model::setInvoker([$this->app, 'invoke']);
        Model::maker(function (Model $model) {
            $config = $this->app->config;

           

            $dateFormat = $model->getDateFormat();

            if (is_null($dateFormat)) {
                // 设置时间戳格式
                $model->setDateFormat($config->get('database.datetime_format', 'Y-m-d H:i:s'));
            }

            $timeField = $config->get('database.datetime_field');
            if (!empty($timeField)) {
                [$createTime, $updateTime] = explode(',', $timeField);
                $model->setTimeField($createTime, $updateTime);
            }
	
	    $isAutoWriteTimestamp = $model->getAutoWriteTimestamp();

            if (is_null($isAutoWriteTimestamp)) {
                // 自动写入时间戳
                $model->isAutoWriteTimestamp($config->get('database.auto_timestamp', 'timestamp'));
            }
        });
    }
}

这个是bug，还设计就是如此？如果设计如此，那不是每个模型都必须设置autoWriteTimestamp属性？