[Bug] fast_forward日志err比率太高了

[PHCSJC]

配置：

• tag: forward_local type: fast_forward args: upstream:

  • addr: tls://223.5.5.5:853 enable_pipeline: true

  • addr: tls://120.53.53.53:853 enable_pipeline: true

第1个正常，第2个err太多，按文档意思是没有返回，这没返回的比率也太高了，把pipeline关了也一样，换成腾讯DoH的也一样，甚至换成UDP err都非常高，fast_forwad对于腾讯DNS的适配有问题？

日志：

"forward_local": {
  "0": {
    "err": 27,
    "latency": {
      "avg": 10,
      "max": 125,
      "min": 4,
      "p25": 5,
      "p50": 5,
      "p75": 6
    },
    "query": 266
  },
  "1": {
    "err": 234,
    "latency": {
      "avg": 91,
      "max": 477,
      "min": 7,
      "p25": 8,
      "p50": 30,
      "p75": 178.25
    },
    "query": 266
  }

[IrineSistiana]

https://github.com/IrineSistiana/mosdns/issues/428