我已经使用UITablelViewCells中的sd_setImage()将缓存的图像添加到UIImageview，如下所示。

imageView.sd_setImage(with: url, placeholderImage: defaultImage) { image, error, cacheType, cacheURL in

}

我的问题是，当加载新的细胞时，图像有时会从服务器重新获取，而实际上它应该在缓存中，而我不知道为什么。在调试期间，我一直在记录cacheType，但它只打印为Int值，范围为0、1、2。

我在SdWebImage文档中找不到任何地方记录的这些值。在一个目标C.h文件中，它被定义为SDImageCacheType类型，如下所示，但我不清楚如何将数字转换为类型。

typedef NS_ENUM(NSInteger, SDImageCacheType) {
    /**
     * For query and contains op in response, means the image isn't available in the image cache
     * For op in request, this type is not available and take no effect.
     */
    SDImageCacheTypeNone,
    /**
     * For query and contains op in response, means the image was obtained from the disk cache.
     * For op in request, means process only disk cache.
     */
    SDImageCacheTypeDisk,
    /**
     * For query and contains op in response, means the image was obtained from the memory cache.
     * For op in request, means process only memory cache.
     */
    SDImageCacheTypeMemory,
    /**
     * For query and contains op in response, this type is not available and take no effect.
     * For op in request, means process both memory cache and disk cache.
     */
    SDImageCacheTypeAll
};

是只有我，还是其他人觉得SDWebImage文档非常令人困惑和难以理解？