src/Leevel/Http/Response.php
protected function contentShouldJson($content): bool
    {
        return $content instanceof IJson ||
               $content instanceof IArray ||
               $content instanceof ArrayObject ||
               $content instanceof JsonSerializable ||
               is_array($content);
    }
protected function contentShouldJson($content): bool
    {
        return $content instanceof IJson ||
               $content instanceof IArray ||
               $content instanceof ArrayObject ||
               $content instanceof JsonSerializable ||
               is_array($content);
    }
可以转换为 JSON.

@param mixed $content

@return bool