NSURLSession - 사진 업로드

iOS10 이하에서AFNetworking이 사진을 업로드하여 메모리 유출이 발생합니다.따라서 다음과 같은 코드로 NSURLSesion을 사용하여 사진을 업로드합니다.

NSString *urlStr = [[self class] createImgUrl];
        
        NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:urlStr]];
        [request setHTTPMethod:@"POST"];
        [request setCachePolicy:NSURLRequestReloadIgnoringCacheData];
        [request setTimeoutInterval:15.f];
        //    boundary=，    
        NSString *content = [[NSString alloc]initWithFormat:@"multipart/form-data; boundary=%@", UploadImageBoundary];
        [request setValue:content forHTTPHeaderField:@"Content-Type"];
        //  token
        [request setValue:gloginManager.token forHTTPHeaderField:@"apptoken"];
        //  host
        if ([ServerConfigManager currentUsedServerType] == ServerType_CUSTOM_IP) {
            [request setValue:@"btr.m.jd.com" forHTTPHeaderField:@"host"];
        }
        
        NSMutableData *requestMutableData = [NSMutableData data];
        NSMutableString *myString = [NSMutableString stringWithFormat:@"--%@\r
", UploadImageBoundary];
        [myString appendString:@"Content-Disposition: form-data; name=\"file\"; filename=\"1.jpg\"\r
"];
        [myString appendString:@"Content-Type: image/jpg\r
\r
"];
        /*        */
        [requestMutableData appendData:[myString dataUsingEncoding:NSUTF8StringEncoding]];
        /*      ，     */
        [requestMutableData appendData:imageData];
        /* --boundary      */
        [requestMutableData appendData:[[NSString stringWithFormat:@"\r
--%@--\r
", UploadImageBoundary] dataUsingEncoding:NSUTF8StringEncoding]];
        request.HTTPBody = requestMutableData;
        
        /*    */
        NSURLSessionDataTask *uploadtask = [[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
            //    
            NSString *jsonStr = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
            DLog(@"finished===========%@", jsonStr);
            NSDictionary *dictionary = [LJUtils toArrayOrDictionaryFromJSONString:jsonStr];
            dispatch_async(dispatch_get_main_queue(), ^{
                callback(YES, dictionary, nil);
            });
        }];
        
        [uploadtask resume];