Set the userinfo.
url_base& set_userinfo( string_view s);
The userinfo is set to the given string, which may contain percent-escapes. Any special or reserved characters in the string are automatically percent-encoded. The effects on the user and password depend on the presence of a colon (':') in the string:
The interpretation of the userinfo as individual user and password components is scheme-dependent. Transmitting passwords in URLs is deprecated.
assert( url( "http://example.com" ).set_userinfo( "user:pass" ).encoded_user() == "user" );
this->size() + s.size().
Strong guarantee. Calls to allocate may throw.
The string to set.
userinfo = [ [ user ] [ ':' password ] ] user = *( unreserved / pct-encoded / sub-delims ) password = *( unreserved / pct-encoded / sub-delims / ":" )