v0.5.0

0.5.0

Performance and reliability release. No breaking changes, and no changes to the
public export surface — safe to upgrade from 0.4.x.

Wins at a glance: up to 45% faster concurrent writes, ~1.8× faster large
selectBytes reads (>256 KB), faster Row lookups and batch writes, a new
diagnostics counter for silent re-query fallbacks, and a reader-isolate crash fix
for diagnostics() under load.

• New API: Diagnostics.unknownDependencyFallbackCount — a cumulative counter
  of writes that conservatively re-queried every registered stream because native
  dependency tracking overflowed its caps (or hit OOM). Surfaces workloads silently
  paying full re-query fan-out on every write, which was previously unobservable
  (#151).
• Bug fix: Database.diagnostics() could intermittently crash a reader isolate
  (SEGV) when polled while readers were mid-query — it toggled SQLite memory
  accounting on live NOMUTEX reader connections. Read workers now bracket each
  request with a real busy guard, and diagnostics reports busy readers as a partial
  snapshot (#156).
• Performance. Each accepted experiment below; see the interactive benchmark dashboard
  for current cross-library numbers.
  • Writer-request pipelining over a persistent reply port — −36% to −45% on
    concurrent standalone writes (#153,
    exp 159).
  • selectBytes native-view transfer — sends a view over the reader's native
    json_buf instead of taking the sacrifice/respawn path; −44% (~1.8×) on large
    (>256 KB) byte reads, at a bounded ~+15 MB RSS (#169,
    exp 174).
  • Row.containsKey identity fast path — pointer-identity membership scan for
    interned keys on schemas ≤ 32 columns; −23% on the containsKey lane
    (#173,
    exp 176).
  • RowSchema lookup fast path — schema-name identity scan with HashMap
    fallback; ~2× faster main-isolate map consumption at 10K rows
    (#150,
    exp 158).
  • Six-parameter batch packing — extends guarded ASCII batch packing to the
    six-parameter shape; executeBatch p50 88 → 75 µs (#141,
    exp 149).
  • Nullable batch packing — nullable-aware packed batch encoder for first-row
    NULL text columns; nullable ASCII 10k×20 25.7 → 21.7 ms (#145,
    exp 150).

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Companion packages released alongside this version: resqlite_vector 0.1.1 and resqlite_js 0.1.1 (now require resqlite: ^0.5.0).