The batched ingest's append-failure catch had zero coverage, and two doc
statements overstated the loss: the Warning said the burst's values were
"dropped", and RecorderStatus.OutboxAppendFailures said "the value was
dropped, not recorded". The outbox contract is prefix-never-orphan, so a
partial-prefix failure leaves entries durably queued that drain normally.
- New test pins the branch: one 3-item burst whose group commit commits a
1-entry prefix then throws => OutboxAppendFailures == 1 (per burst, not
per value), TotalRecorded == 0, actor alive, and the prefix still reaches
the writer via the post-failure DrainTick (drainInterval 30s, so the
steady cadence cannot account for it). Falsified twice: counting per item
and dropping the drain nudge each turn it red.
- Second test pins the OperationCanceledException filter from its
observable side - a cancel that is NOT shutdown is metered, not swallowed.
Removing the 'when (_lifetime.IsCancellationRequested)' turns it red. The
shutdown side has no cheap seam (the counter dies with the actor).
- Docs corrected: OutboxAppendFailures counts FAILED BATCH APPENDS, one per
burst whatever its size (a granularity change from the per-value era), and
is not a count of values lost; TotalRecorded under-counts when a commit
fails after a partial prefix. Log message says "failed to append" and
names the prefix. No functional change beyond the message string.
Also folds in the DrainBatchSize default alignment behind 0298a0b9: the
recorder's two ctor defaults and its non-positive fallback still said 64
while ContinuousHistorizationOptions.DrainBatchSize now defaults to 1024.
No test pinned the old 64.
Joseph Doherty
451273c860