In case of current account session need refreshing, after calling [ODItemContentRequest downloadWithCompletion], the value of [ODURLSessionDownloadTask.progress] will still be 'nil' until account session has been refreshed so there is no way to add observer to the progress property.
In case of current account session need refreshing, after calling [ODItemContentRequest downloadWithCompletion], the value of [ODURLSessionDownloadTask.progress] will still be 'nil' until account session has been refreshed so there is no way to add observer to the progress property.