`git annex unused --from=$remote` and `git annex info $remote`
buffer the list of keys that have uncommitted journalled changes
in memory. This is due to Annex.Branch.files's which reads all the
files in the journal into a buffer.

Note that the list of keys in the branch *does* stream in, so this
is only really a problem when using annex.alwayscommit=false to build
up big git-annex branch commits via the journal. Or using annex.private,
since the private journal can build up a lot of keys in it.

An attempt at making it stream via unsafeInterleaveIO failed miserably
and that is not the right approach. This would be a good place to use
ResourceT, but it might need some changes to the Annex monad to allow
combining the two. --[[Joey]]

> This used to also affect --all and using git-annex in a bare repo, but
> that was avoided by using the overBranchFileContents interface. This
> suggests that changing to that interface in unused and info would be a
> solution.

[[!tag confirmed]]

[[!meta title="improve memory usage of unused and info when the journal contains a lot of files"]]