Add the only headers arg convenience initializer

SDWebImage/Core/SDWebImageDownloaderRequestModifier.h

@@ -39,18 +39,16 @@ typedef NSURLRequest * _Nullable (^SDWebImageDownloaderRequestModifierBlock)(NSU
  */
 @interface SDWebImageDownloaderHTTPRequestModifier : NSObject <SDWebImageDownloaderRequestModifier>
 
+/// Create the request modifier with HTTP Headers
+/// @param headers HTTP Headers. Case insensitive according to HTTP/1.1(HTTP/2) standard. The headers will overide the same fileds from original request.
+/// @note This is for convenience, if you need code to control the logic, use `SDWebImageDownloaderRequestModifier` instead
+- (nonnull instancetype)initWithHeaders:(nullable NSDictionary<NSString *, NSString *> *)headers;
+
 /// Create the request modifier with HTTP Method, Headers and Body
 /// @param method HTTP Method, nil means to GET.
 /// @param headers HTTP Headers. Case insensitive according to HTTP/1.1(HTTP/2) standard. The headers will overide the same fileds from original request.
 /// @param body HTTP Body
 /// @note This is for convenience, if you need code to control the logic, use `SDWebImageDownloaderRequestModifier` instead
-- (nonnull instancetype)initWithMethod:(nullable NSString *)method headers:(nullable NSDictionary<NSString *, NSString *> *)headers body:(nullable NSData *)body;
-
-/// Create the request modifier with HTTP Method, Headers and Body
-/// @param method HTTP Method, nil means to GET.
-/// @param headers HTTP Headers. Case insensitive according to HTTP/1.1(HTTP/2) standard. The headers will overide the same fileds from SDWebImageDownloader global configuration.
-/// @param body HTTP Body
-/// @note This is for convenience, if you need code to control the logic, use `SDWebImageDownloaderRequestModifier` instead
-+ (nonnull instancetype)requestModifierWithMethod:(nullable NSString *)method headers:(nullable NSDictionary<NSString *, NSString *> *)headers body:(nullable NSData *)body;
+- (nonnull instancetype)initWithMethod:(nullable NSString *)method headers:(nullable NSDictionary<NSString *, NSString *> *)headers body:(nullable NSData *)body NS_DESIGNATED_INITIALIZER;
 
 @end

SDWebImage/Core/SDWebImageDownloaderRequestModifier.m

@@ -48,6 +48,10 @@
 
 @implementation SDWebImageDownloaderHTTPRequestModifier
 
+- (instancetype)initWithHeaders:(NSDictionary<NSString *,NSString *> *)headers {
+    return [self initWithMethod:nil headers:headers body:nil];
+}
+
 - (instancetype)initWithMethod:(NSString *)method headers:(NSDictionary<NSString *,NSString *> *)headers body:(NSData *)body {
     self = [super init];
     if (self) {
@@ -58,11 +62,6 @@
     return self;
 }
 
-+ (instancetype)requestModifierWithMethod:(NSString *)method headers:(NSDictionary<NSString *,NSString *> *)headers body:(NSData *)body {
-    SDWebImageDownloaderHTTPRequestModifier *requestModifier = [[SDWebImageDownloaderHTTPRequestModifier alloc] initWithMethod:method headers:headers body:body];
-    return requestModifier;
-}
-
 - (NSURLRequest *)modifiedRequestWithRequest:(NSURLRequest *)request {
     NSMutableURLRequest *mutableRequest = [request mutableCopy];
     mutableRequest.HTTPMethod = self.method;

SDWebImage/Core/SDWebImageDownloaderResponseModifier.h

@@ -39,18 +39,16 @@ typedef NSURLResponse * _Nullable (^SDWebImageDownloaderResponseModifierBlock)(N
  */
 @interface SDWebImageDownloaderHTTPResponseModifier : NSObject <SDWebImageDownloaderResponseModifier>
 
+/// Create the response modifier with HTTP Headers. Status code defaults to 200.
+/// @param headers HTTP Headers. Case insensitive according to HTTP/1.1(HTTP/2) standard. The headers will overide the same fileds from original response.
+/// @note This is for convenience, if you need code to control the logic, use `SDWebImageDownloaderResponseModifier` instead
+- (nonnull instancetype)initWithHeaders:(nullable NSDictionary<NSString *, NSString *> *)headers;
+
 /// Create the response modifier with HTTP Version, Status Code and Headers
 /// @param version HTTP Version, nil means "HTTP/1.1"
 /// @param statusCode HTTP Status Code
 /// @param headers HTTP Headers. Case insensitive according to HTTP/1.1(HTTP/2) standard. The headers will overide the same fileds from original response.
 /// @note This is for convenience, if you need code to control the logic, use `SDWebImageDownloaderResponseModifier` instead
-- (nonnull instancetype)initWithVersion:(nullable NSString *)version statusCode:(NSInteger)statusCode headers:(nullable NSDictionary<NSString *, NSString *> *)headers;
-
-/// Create the response modifier with HTTP Version, Status Code and Headers
-/// @param version HTTP Version, nil means "HTTP/1.1". See available value in CFNetwork like `kCFHTTPVersion1_1`.
-/// @param statusCode HTTP Status Code
-/// @param headers HTTP Headers. Case insensitive according to HTTP/1.1(HTTP/2) standard. The headers will overide the same fileds from original response.
-/// @note This is for convenience, if you need code to control the logic, use `SDWebImageDownloaderResponseModifier` instead
-+ (nonnull instancetype)responseModifierWithVersion:(nullable NSString *)version statusCode:(NSInteger)statusCode headers:(nullable NSDictionary<NSString *, NSString *> *)headers;
+- (nonnull instancetype)initWithVersion:(nullable NSString *)version statusCode:(NSInteger)statusCode headers:(nullable NSDictionary<NSString *, NSString *> *)headers NS_DESIGNATED_INITIALIZER;
 
 @end

SDWebImage/Core/SDWebImageDownloaderResponseModifier.m

@@ -49,6 +49,10 @@
 
 @implementation SDWebImageDownloaderHTTPResponseModifier
 
+- (instancetype)initWithHeaders:(NSDictionary<NSString *,NSString *> *)headers {
+    return [self initWithVersion:nil statusCode:200 headers:headers];
+}
+
 - (instancetype)initWithVersion:(NSString *)version statusCode:(NSInteger)statusCode headers:(NSDictionary<NSString *,NSString *> *)headers {
     self = [super init];
     if (self) {
@@ -59,11 +63,6 @@
     return self;
 }
 
-+ (instancetype)responseModifierWithVersion:(NSString *)version statusCode:(NSInteger)statusCode headers:(NSDictionary<NSString *,NSString *> *)headers {
-    SDWebImageDownloaderHTTPResponseModifier *responseModifier = [[SDWebImageDownloaderHTTPResponseModifier alloc] initWithVersion:version statusCode:statusCode headers:headers];
-    return responseModifier;
-}
-
 - (NSURLResponse *)modifiedResponseWithResponse:(NSURLResponse *)response {
     if (![response isKindOfClass:NSHTTPURLResponse.class]) {
         return response;