The goodbye table of directory entries is cached in a LRU cache to speed up
subsequent accesses.
This is especially important for directories with many entries, as then the
readdirplus callback is called repeatedly because of the limited reply buffer
size.
`DirectoryEntry`s are cached for subsequent access in their own LRU cache,
independent of the goodbye tables.
In order to avoid borrow conflicts, the `Context` provides a fn as_mut_refs
as well as a fn run_with_context_refs.
Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>