ty

Ok, next step, - [ ] uses trust-dns-client for higher level APIs - [ ] making DNS queries sent by TCP/UDP configurable

Should we reuse [trust-dns-client](https://crates.io/crates/trust-dns-client) to implement DNS relay? @madeye

But that will end up to link most of the `trust-dns`, binary size will be large.

Could we reuse the global DNS resolver? @madeye , the one in `src/relay/dns_resolver/`

`dns_relay` send queries simultaneously by direct connections and proxy connections. For direct connections, they actually work the same as `trust-dns-resolver` internally but lack of many other things, such as lookup...

`local_dns_path` is not used anywhere in this project.

Okay... I will keep it until madeye finishes all his works.

Yes, I also highly suggest that we can use `trust-dns-client`.

Its API allows customization of the underlying connection.

> The system has enough resources to create UDP sockets, it should not fail to bind a new UDP port, Your error is: `Err(Os { code: 98, kind: AddrInUse, message:...