I made a large change to a repository by essentially renaming a directory which contains a large number of files (i.e. `git mv from_dir/ to_dir/`). The output of `git diff` is quite small (13 megabytes), but uploading this diff with `arc diff` takes a very long time (a number of hours) and eventually fails. As an alternative, I tried uploading the `git diff` output manually at `/differential/diff/create/`, but this timed out after 30 seconds.
Running `arc export --arcbundle` also takes a very long time (almost three hours) and ended up producing a 128MB bundle. Looking at the output from `--trace`, most of the time was spent running either `git ls-tree 'HEAD' -- '$PATH'` or `git cat-file blob '$COMMIT_HASH'` for every file in the subdirectory that was moved.