When uploading to an Amazon S3 storage class, using this module:
- Smallish files (~6MB): the progress sits at 0% until jumping abruptly to 100% on completion (which takes a copule of minutes on my slow connection).
- Larger files (~30 MB): the progress jumps to some arbitrary number immediately (23%, 66%, 76%), then stays there until jumping abruptly to 100% on completion (which takes several minutes on my slow connection).
Meanwhile Chrome's status message simply reads "Waiting for [my server name]," and gives the spinning cursor. Seeing this for several minutes, with no apparent progress on the upload, obviously gives the impression that the upload has broken.
Pecl upload progress bar is tested and working fine for uploads to my public files directory (jumps around a little, but will usually advance every couple of seconds or so).