Proxy DNS failover v/s Load balancing

Here is a config snippet:
```
proxy-dns: true
proxy-dns-port: 5053
proxy-dns-upstream:
- https://.cloudflare-gateway.com/dns-query
- https://1.1.1.1/dns-query
```

Will this load balance across both (which is not my intention) or use the 1st one, and failover to the second one in case of failure?

I can see that the servers are passed to coredns, but then I could not traverse further to see what coredns does with it.
https://github.com/cloudflare/cloudflared/blob/59cae0f622a33355d320fc4701b9720197b788d2/tunneldns/tunnel.go#L95-L97
https://github.com/coredns/coredns/blob/master/core/dnsserver/server.go

Today I observed an outage of my gateway whereas 1.1.1.1 was still up. I would like to use my gateway as much as possible till it fails and switch over to the rest. Is this possible?