Objective-C program upload file to Azure Blob Storage with progress indicator

Main.m

#import <AZSClient/AZSClient.h>

NSString *const AZURE_STORAGE_CONNECTION_STRING = @"DefaultEndpointsProtocol=https;AccountName=(your account name);AccountKey=(your account key);EndpointSuffix=core.windows.net";
NSString *const AZURE_STORAGE_CONTAINER = @"files";
NSString *const LOCAL_FILE_FILEPATH = @"/Users/dino/A.mp4";
NSString *const LOCAL_FILE_FILENAME = @"A.mp4";

NSError *error;
AZSCloudStorageAccount *account = [AZSCloudStorageAccount accountFromConnectionString:AZURE_STORAGE_CONNECTION_STRING error:&error];
AZSCloudBlobClient *client = [account getBlobClient];
AZSCloudBlobContainer *container = [client containerReferenceFromName:AZURE_STORAGE_CONTAINER];

[container createContainerIfNotExistsWithCompletionHandler:^(NSError *error, BOOL exists) {
    @autoreleasepool {
        AZSCloudBlockBlob *blob = [container blockBlobReferenceFromName:LOCAL_FILE_FILENAME];
        
        NSUInteger size = [[[NSFileManager defaultManager] attributesOfItemAtPath:LOCAL_FILE_FILEPATH error:&error] fileSize];
        
        NSInputStream *stream = [NSInputStream inputStreamWithFileAtPath:LOCAL_FILE_FILEPATH];
        
        AZSOperationContext *operationContext = [[AZSOperationContext alloc] init];
        operationContext.sendingRequest = ^(NSMutableURLRequest *request, AZSOperationContext *context) {
            NSNumber *number = [stream propertyForKey:NSStreamFileCurrentOffsetKey];
            if (number != nil) {
                NSUInteger pos = [number longValue];
                float percentage = ((float)pos / size) * 100;
                NSLog(@"current %ld of %ld, %f%% completed", pos, size, percentage);
            }
        };
        
        NSLog(@"upload started.");
        
        [blob uploadFromStream:stream accessCondition:nil requestOptions:nil operationContext:operationContext completionHandler:^(NSError *error) {
             NSLog(@"upload done.");
             exit(0);
        }];
    }
}];

Does this approach handle loss in Internet connection or App switching in iOS?

Did you have a problem with the streamfilecurrentoffset variable? It is returning nil for me.