Eg when the destination is logged as containing a file, skip
actively checking that it does contain it.
Note that --fast does not prevent other verifications of content
location that are done in a copy --from --to. Perhaps it could, but this
change will already avoid the real unnecessary work of operating on
files that are already in the remote.
And avoiding other verifications
might cause it to fail if the location log thinks that --to does not
contain the content but does. Such complications with `git-annex copy
--to remote --fast` led to commit d006586cd0
which added a note that gets displayed when that fails, mentioning it
might be due to --fast being enabled.
copy --from --to is already complicated enough without needing to worry
about such edge cases, so continuing to doing some verification of
content location after the initial --fast filtering seems ok.
Sponsored-by: Dartmouth College's DANDI project
git-annex allows managing large files with git, without storing the file
contents in git. It can sync, backup, and archive your data, offline
and online. Checksums and encryption keep your data safe and secure. Bring
the power and distributed nature of git to bear on your large files with
git-annex.
For documentation, see doc/ or <https://git-annex.branchable.com/>
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