Thanks for the post!
Unfortunately, we do not offer chunked uploads as a feature of our Public API at the moment. While we support uploads up to 50 GB file size, we are aware that large file uploads are fragile and end up in connection failures or with other issues. To mitigate this, we are working on a 'Resumable Uploads' feature; similar to 'Chunked Uploading'. I cannot provide an ETA on this right now, but we are working on this. With the addition of 'Resumable Uploads', uploads may still fail as they are uploading, but they will resume from where they failed in the next try.
It looks like this feature is in an alpha/beta stage and is fully undocumented, but works. The folks over at rclone seem to have researched and figured it out. For more information read Resume uploads #87