Replaces the streaming request/result API with caller-owned items and
consolidates the content options, following the Job execution performance
design.
- `Item`, `BatchSource` and `Run` replace `StreamRequest`, `StreamResult`,
`StreamSource`, `StreamSink` and `RunStream`. Every accepted item receives
exactly one terminal callback from a single goroutine and without doing
I/O; an item ACP cannot process reports `Failed`, and a completion carries
one outcome per requested target in request order with its error identity
preserved. A graceful stop stops feeding, finishes the items in flight and
reports the rest, and a hard stop abandons per-item accounting.
- One `HashPolicy` replaces `WithHash`, `WithSignatureCache` and
`ForceRehash`. A stored hash is read whenever the policy uses the cache,
reused only where the policy allows it, and refreshed only when it differs.
- A source-only `WithReadMode` selects buffered (the default) or mapped
reads, and buffered sources open with `O_NOATIME` where the platform has
it. `LinearDevice` keeps request ordering, append targets and abort-on-error
but no longer selects the read mode.
- `Overwrite` becomes a target-device option, `WithReadBuffer` sets the read
buffer, and `SelectFiles` returns the entries the command line copies,
replacing `AccurateJob`, `WildcardJob` and the walk options.
- Copy consumers share one reference-counted chunk buffer each from a common
pool, and the per-item write goroutines finish before the result channel
closes, so no finished item can be dropped.
The command line tools, the documentation and the test suite move with the
API, including semantic tests for the callback contract, the stop and drain
paths, the hash policy matrix and the read modes.
Samuel Cui
Samuel N Cui