Rule for absolute-URI
<include/boost/url/rfc/absolute_uri_rule.hpp>
constexpr
_implementation-defined_ absolute_uri_rule = {};
using value_type = url_view;
system::result< url_view > rv = grammar::parse( "http://example.com/index.htm?id=1", absolute_uri_rule );
absolute-URI = scheme ":" hier-part [ "?" query ]
hier-part = "//" authority path-abempty
/ path-absolute
/ path-rootless
/ path-empty