Repository: SDWebImage/SDWebImage
File: SDWebImage/SDWebImageDownloader.h (C/C++)

Code before:
    SDWebImageDownloaderScaleDownLargeImages = 1 << 8,
    
    /**
     * By default, we will decode the image in the background during cache query and download from the network. This can help to improve performance because when rendering image on the screen, it need to be firstly decoded. But this happen on the main queue by Core Animation.
     * However, this process may increase the memory usage as well. If you are experiencing a issue due to excessive memory consumption, This flag can prevent decode the image.
     */
    SDWebImageDownloaderAvoidDecodeImage = 1 << 9,
    
    /**
     * By default, we decode the animated image. This flag can force decode the first frame only and produece the static image.
     */
    SDWebImageDownloaderDecodeFirstFrameOnly = 1 << 10,
    
    /**
     * By default, for `SDAnimatedImage`, we decode the animated image frame during rendering to reduce memory usage. This flag actually trigger `preloadAllAnimatedImageFrames = YES` after image load from network
     */
    SDWebImageDownloaderPreloadAllFrames = 1 << 11
};

FOUNDATION_EXPORT NSString * _Nonnull const SDWebImageDownloadStartNotification;
FOUNDATION_EXPORT NSString * _Nonnull const SDWebImageDownloadStopNotification;

typedef SDImageLoaderProgressBlock SDWebImageDownloaderProgressBlock;
typedef SDImageLoaderCompletedBlock SDWebImageDownloaderCompletedBlock;

@protocol SDWebImageDownloaderOperation;

/**
 *  A token associated with each download. Can be used to cancel a download
 */
@interface SDWebImageDownloadToken : NSObject <SDWebImageOperation>

/**
 Cancel the current download.
 */
- (void)cancel;

/**
 The download's URL.
 */
@property (nonatomic, strong, nullable, readonly) NSURL *url;

/**
 The download's request.
 */
@property (nonatomic, strong, nullable, readonly) NSURLRequest *request;

/**
 The download's response.
 */
@property (nonatomic, strong, nullable, readonly) NSURLResponse *response;

Review comment (suggestion):
Emm.....What does this used for ? The `SDWebImageDownloadToken` just use a internal class category for write access and init (Actually, the `init` method should be marked as `NS_UNAVAILBLE`). So we don't need to change anything on the header files.

Code after:
    SDWebImageDownloaderScaleDownLargeImages = 1 << 8,
    
    /**
     * By default, we will decode the image in the background during cache query and download from the network. This can help to improve performance because when rendering image on the screen, it need to be firstly decoded. But this happen on the main queue by Core Animation.
     * However, this process may increase the memory usage as well. If you are experiencing a issue due to excessive memory consumption, This flag can prevent decode the image.
     */
    SDWebImageDownloaderAvoidDecodeImage = 1 << 9,
    
    /**
     * By default, we decode the animated image. This flag can force decode the first frame only and produece the static image.
     */
    SDWebImageDownloaderDecodeFirstFrameOnly = 1 << 10,
    
    /**
     * By default, for `SDAnimatedImage`, we decode the animated image frame during rendering to reduce memory usage. This flag actually trigger `preloadAllAnimatedImageFrames = YES` after image load from network
     */
    SDWebImageDownloaderPreloadAllFrames = 1 << 11
};

FOUNDATION_EXPORT NSString * _Nonnull const SDWebImageDownloadStartNotification;
FOUNDATION_EXPORT NSString * _Nonnull const SDWebImageDownloadStopNotification;

typedef SDImageLoaderProgressBlock SDWebImageDownloaderProgressBlock;
typedef SDImageLoaderCompletedBlock SDWebImageDownloaderCompletedBlock;

/**
 *  A token associated with each download. Can be used to cancel a download
 */
@interface SDWebImageDownloadToken : NSObject <SDWebImageOperation>

/**
 Cancel the current download.
 */
- (void)cancel;

/**
 The download's URL.
 */
@property (nonatomic, strong, nullable, readonly) NSURL *url;

/**
 The download's request.
 */
@property (nonatomic, strong, nullable, readonly) NSURLRequest *request;

/**
 The download's response.
 */
@property (nonatomic, strong, nullable, readonly) NSURLResponse *response;

@end