Function rebuildTransport

src/bridge/remoteBridgeCore.ts:477–527

(
    fresh: RemoteCredentials,
    cause: Exclude<ConnectCause, 'initial'>,
  )

  // the flag — moving it here would be too late to prevent a double /bridge
  // fetch, and each fetch bumps epoch.
  async function rebuildTransport(
    fresh: RemoteCredentials,
    cause: Exclude<ConnectCause, 'initial'>,
  ): Promise<void> {
    connectCause = cause
    // Queue writes during rebuild — once /bridge returns, the old transport's
    // epoch is stale and its next write/heartbeat 409s. Without this gate,
    // writeMessages adds UUIDs to recentPostedUUIDs then writeBatch silently
    // no-ops (closed uploader after 409) → permanent silent message loss.
    flushGate.start()
    try {
      const seq = transport.getLastSequenceNum()
      transport.close()
      transport = await createV2ReplTransport({
        sessionUrl: buildCCRv2SdkUrl(fresh.api_base_url, sessionId),
        ingressToken: fresh.worker_jwt,
        sessionId,
        epoch: fresh.worker_epoch,
        heartbeatIntervalMs: cfg.heartbeat_interval_ms,
        heartbeatJitterFraction: cfg.heartbeat_jitter_fraction,
        initialSequenceNum: seq,
        getAuthToken: () => fresh.worker_jwt,
        outboundOnly,
      })
      if (tornDown) {
        // Teardown fired during the async createV2ReplTransport window.
        // Don't wire/connect/schedule — we'd re-arm timers after cancelAll()
        // and fire onInboundMessage into a torn-down bridge.
        transport.close()
        return
      }
      wireTransportCallbacks()
      transport.connect()
      connectDeadline = setTimeout(
        onConnectTimeout,
        cfg.connect_timeout_ms,
        connectCause,
      )
      refresh.scheduleFromExpiresIn(sessionId, fresh.expires_in)
      // Drain queued writes into the new uploader. Runs before
      // ccr.initialize() resolves (transport.connect() is fire-and-forget),
      // but the uploader serializes behind the initial PUT /worker. If
      // init fails (4091), events drop — but only recentPostedUUIDs
      // (per-instance) is populated, so re-enabling the bridge re-flushes.
      drainFlushGate()
    } finally {
      // End the gate on failure paths too — drainFlushGate already ended
      // it on success. Queued messages are dropped (transport still dead).
      flushGate.drop()
    }
  }

  // ── 8. 401 recovery (OAuth refresh + rebuild) ───────────────────────────
  async function recoverFromAuthFailure(): Promise<void> {