Progressbar on file-upload to Amazon S3 for iOS?

Progressbar on file-upload to Amazon S3 for iOS?

I was using the services from Parse a while back, and they had implemented
an amazing feature for uploading data, with a method something like this:
PFFile *objectToSave...; //An image or whatever, wrapped in a Parse-file
[objectToSave saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
//Do stuff after upload is complete
} progressBlock:^(int percentDone) {
[someLabel setText:[NSString stringWithFormat:@"%i%@",
percentDone, @"%"]];
}];
Which let me keep track of the file-upload. Since Parse only let me upload
max 10mb files, I chose to move to the cloud-area to explore a bit. I've
been testing with Amazon's S3-service now, but the only way I can find how
to upload data is by calling [s3 putObject:request];. This will occupy the
main thread until it's done, unless I run it on another thread. Either
way, I have no idea of letting my users know how far the upload has come.
Is there seriously no way of doing this? I read that some
browser-API-version of S3's service had to use Flash, or set all uploads
to go through another server, and keep track on that server, but I won't
do either of those. Anyone? Thanks.
My users are supposed to be uploading video with sizes up to 15mb, do I
have to let them stare at a spinning wheel for an unknown amount of time?
With a bad connection, they might have to wait for 15 minutes, but they
would stare at the screen in hope the entire time.