X_BENCH_STREAM_CLOSED
Means
the restart benchmark's stdout closed before the line it was waiting for
Typical cause
the shard or the server process ended without printing its READY or FINAL line, so the orchestrator was reading a stream that could never answer — the measurement it was about to report was never taken
Fix
bun run scripts/bench/restart-bench.ts --clients 50000 --out scripts/bench/results/50k-restart.json