Function http_with_url::request::get_target_components

pub fn get_target_components<T>(
    request: &Request<T>
) -> Result<(&str, &str, &str)>

Get data for pseudo-headers or request-line/Host header.

Return data:

1. :scheme pseudo header
2. :authority pseudo header / Host header field
3. :path pseudo header / request-target in request line

Fails if the authority is empty, or the request targets the whole server but the path is not empty.