We're limiting the bandwidth of our upload to 500KBps, when we upload files that are about 1GB.
For some reason, even though we're within AWS's network - we need several retries.
Current throttling's behavior is that on each retry - the bandwidth drops further - which increases the chances we'll need another retry.
So, once we start retrying - the chances that our upload will succeed becomes slim.
By patching our copy of S3.py, not to reduce the bandwidth with each retry - we've considerably increased the chances of a successful upload.