The SectorSource/Sink agent and the WritebackFile-rename agent both
branched from main concurrently; the sector branch wrote against the
0.17 Writer name and only the rename branch knew about WritebackFile.
This integration commit reconciles the two: FileSectorSink::create /
::open / the inner-field type all use WritebackFile directly, and the
module-level + struct-level docs are corrected.
Splits the unidirectional read trait from a (planned) write trait at
the sector level, eliminating runtime "wrong direction" potential.
Keeps SectorReader alive as a pre-deprecation alias via blanket impl
so existing callers compile unchanged through the migration window.
Adds DecryptingSectorSource decorator: wrap any SectorSource in this
to get plaintext sectors out. Replaces the duplicate decrypt code
paths in sweep_pipeline and DiscStream (those migrations are
follow-up commits).
The formal #[deprecated] attribute on SectorReader is held back to a
follow-up commit because internal call sites in disc/, udf/, mux/,
and verify/ still go through the legacy trait, and the CI gauntlet
treats deprecation lints as errors. Behavioural intent — "this trait
is going away" — is documented on the trait itself.
See (internal)/memory/0_18_redesign.md.
Single contributor: MattJackson.
MattJackson