[#F0887477DC879F9C7AAC34D6FB4538E1BFB31DC4]
Constructor
url() noexcept;
Default constructed urls contain a zero-length string. This matches the grammar for a relative-ref with an empty path and no query or fragment.
url u;
this->empty() == true
Constant.
Throws nothing.
relative-ref = relative-part [ "?" query ] [ "#" fragment ]