Function global_dns_resolver 

pub fn global_dns_resolver() -> BoxDnsResolver

Get the global DnsResolver.

This is a shared once-time init dns resolver used by default in rama. By default it is created in a lazy fashion using HickoryDns::default.

Use init_global_dns_resolver or try_init_global_dns_resolver to overwrite the global DnsResolver. This has to be done as early as possible, as it fails if the global resolver was already initialised (e.g. using the default).