How to upload a file larger than 2 GB? I have seen [this example](https://github.com/machinezone/IXWebSocket/blob/4f17cd5e7498bdca4cf1089eb1d33765981bf913/ixsentry/ixsentry/IXSentryClient.cpp#L261), but uploading files in string format can cause OOM if the file size is too large.