pub fn prune(root: &Path, limit: u64) -> Result<Pruned>Expand description
Evicts least recently used entries until the cache holds at most limit
bytes, and removes what no entry needs. Another prune in progress makes
this one return without doing anything.
Runs call this after every run, so a cache under its limit is only summed: the full pass, which reads every manifest, runs when the cache is over its limit or when the last full pass is more than an hour old.