{
  "synthetic": true,
  "purpose": "接口响应格式教学样例，不是在线 API 服务地址",
  "items": [
    {
      "city": "虚构甲市",
      "service": "气象查询",
      "requests": 200,
      "latency_ms": 40
    },
    {
      "city": "虚构乙市",
      "service": "公交查询",
      "requests": 300,
      "latency_ms": 60
    }
  ]
}