审查这段生成的预订故障转移路径，检查其一致性与安全重试能力。
预订库存时不得让库存低于零，必须保持单一写入权威，并允许调用者安全重试未知结果。
JavaScript
async function reserve(actor, itemId, quantity, replicas) {
if (!actor.canReserve) throw new Error('forbidden');
const requestId = crypto.randomUUID();
const reachable = replicas.filter((replica) => replica.isHealthy());
for (const replica of reachable) {
try {
const result = await Promise.race([
replica.reserve({ itemId, quantity }),
timeout(100).then(() => ({ ok: false })),
]);
if (result.ok) return { ok: true, requestId };
} catch {
continue;
}
}
const cached = replicas[0].cache.get(itemId);
cached.stock -= quantity;
replicas[0].cache.set(itemId, cached);
return { ok: true, requestId, degraded: true };
}
生成代码仅作示例，不代表任何特定模型