Function deltachat::net::dns::lookup_host_with_cache

pub(crate) async fn lookup_host_with_cache(
    context: &Context,
    hostname: &str,
    port: u16,
    alpn: &str,
    load_cache: bool,
) -> Result<Vec<SocketAddr>>

Looks up hostname and port using DNS and updates the address resolution cache.

alpn is used to sort DNS results by the time we have successfully connected to the IP address using given alpn. If result sorting is not needed or alpn is unknown, pass empty string here, e.g. for HTTP requests or when resolving the IP address of SOCKS proxy.

If load_cache is true, appends cached results not older than 30 days to the end or entries from fallback cache if there are no cached addresses.