Tunnel hangs after upstream router restart

The tunnel thinks everything is fine but the Teams web UI shows the tunnel is inactive. Attempts to connect to protected resources end up in a "too many redirects" loop.

```
$ cftun
Trying to pull docker.io/cloudflare/cloudflared:2021.10.2...
Getting image source signatures
Copying blob 6b34ec2e9ecc done
Copying blob 9411f38bb959 done
Copying blob 792ac47b91a1 done
Copying config 364d068eff done
Writing manifest to image destination
Storing signatures
2021-10-15T03:06:23Z INF Starting tunnel tunnelID=82bee42b-83c7-4800-86ab-b6755b1be1b6
2021-10-15T03:06:23Z INF Version 2021.10.2-dev
2021-10-15T03:06:23Z INF GOOS: linux, GOVersion: go1.17.1, GoArch: amd64
2021-10-15T03:06:23Z INF Settings: map[config:/etc/cloudflared/ha.yaml cred-file:/etc/cloudflared/82bee42b-83c7-4800-86ab-b6755b1be1b6.json credentials-file:/etc/cloudflared/82bee42b-83c7-4800-86ab-b6755b1be1b6.json metrics:0.0.0.0:12345 no-autoupdate:true]
2021-10-15T03:06:23Z INF cloudflared will not automatically update when run from the shell. To enable auto-updates, run cloudflared as a service: https://developers.cloudflare.com/cloudflare-one/connections/connect-apps/run-tunnel/run-as-service
2021-10-15T03:06:23Z INF Generated Connector ID: 12050563-9a9d-4fcd-b361-254c40b5b816
2021-10-15T03:06:23Z INF Initial protocol http2
2021-10-15T03:06:23Z INF Starting metrics server on [::]:12345/metrics
2021-10-15T03:06:23Z INF Connection 05207bf5-9047-4e1a-a26d-f8e304b0874d registered connIndex=0 location=IAD
2021-10-15T03:06:24Z INF Connection f42347e5-42a1-4958-bcba-f3ab0d79d460 registered connIndex=1 location=IAD
2021-10-15T03:06:25Z INF Connection 0ec3d734-aebd-4f5f-a31c-f1440e8a81f2 registered connIndex=2 location=IAD
2021-10-15T03:06:26Z INF Connection 42b8bf9e-225d-4a45-86f1-f4839e7c9736 registered connIndex=3 location=IAD
```

Router restarts here. No more logs are printed to the cftun console.

```
$ curl -s localhost:12345/ready | jq .
{
"status": 200,
"readyConnections": 4
}
```

The ready endpoint says everything is fine but the Teams console has marked the tunnel as INACTIVE. This is fairly reproducible for me. Am I missing a setting on the tunnel client?

```
$ cat ~/.cloudflared/ha.yaml
tunnel: 82bee42b-83c7-4800-86ab-b6755b1be1b6
credentials-file: /etc/cloudflared/82bee42b-83c7-4800-86ab-b6755b1be1b6.json
metrics: 0.0.0.0:12345

ingress:
- hostname: XXX
service: XXX
- service: http_status:404
```

Riproduci lo scenario di riavvio del router con la configurazione ~/.cloudflared/ha.yaml fornita, osservando la console cftun. Controlla localhost:12345/ready insieme allo stato del tunnel Teams e alle richieste alle risorse protette. È completato quando il tunnel si ripristina in modo coerente dopo il riavvio, segnala uno stato accurato ed evita il loop di reindirizzamento.

Scritto dal modello di indicizzazione a partire dal testo della issue.