Expand description
Leader-side replication server for FixedStore.
- Spawns a TCP acceptor thread.
- On the first accepted follower connection, installs SPSC producers into every shard (lazy install — Mitigation B of spec §5/§7).
- Each accepted connection spawns a per-shard serve thread that does Phase 1 (full scan catch-up, honoring FLAG_EMPTY_STATE to skip DELETED slots) then Phase 2 (SPSC streaming) if the per-shard consumer is still available.
Single-follower-streaming-per-shard limitation (v1): once the SPSC consumer for a shard has been handed to the first follower, subsequent followers get catch-up only — they idle after CaughtUp.