Improve network upload

Currently there is no optimization for sending a large file over the network. This is not much of a problem for making regular network requests which are small enough, but it's not a good user experience when trying to upload files because it takes several seconds.

Look into how to improve this

Start by locating the network upload entry point and tracing how large files are currently sent. Compare the existing path with the regular request path described in the issue, then define a measurable improvement for large-file upload time before changing behavior. Done means large uploads complete with a demonstrably better user experience.

Written by the indexing model from the issue text.