Answering #45 — can a fitted `History` be persisted — needed to know
whether `converge` reaches a fixed point determined by the events alone,
or one that depends on the message state it started from. It is the
former, and that is worth a test rather than a comment.
`tests/ingestion_equivalence.rs` varies how events are batched but
converges only at the end. These converge *between* batches, which is
the path a caller takes when it fits, serves, then ingests more.
Measured divergence from a single fit over the same events: 6.2e-13 for
an append strictly later than every existing slice, 8.9e-11 for one
interleaved with them. Both at the convergence tolerance. The design
question guessed the interleaved case might be weaker; it is not, and
the reason is that Through Time revises the past on every converge
anyway, so doing it in two steps is not a special case.
Also pins that re-converging an unchanged history costs one iteration.
Measured on a 2000-event fixture that is 0.91ms against 365ms cold — the
fact that makes a restored snapshot worth having at all.
Refs #45
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011hcFjNDmHXZF8URGLku5zZ
logaritmiskandClaude Opus 5
5d36fa1008