s3: how to track upload progress

[aeneasr]

I'd like to track the how far the current progress of an upload is. This is how I'm uploading:

    svc := s3.New(h.awsSess)
    uploader := s3manager.NewUploaderWithClient(svc)
    _, err = uploader.Upload(&s3manager.UploadInput{
        Body:                 reader,
        Bucket:               &h.bucketName,
                // ....
    })

I couldn't find anything on that topic and it does not look like there's anything in the code for it.