std::ostream&
operator<<(
    std::ostream& os,
    ipv4_address const& addr);

std::ostream&
operator<<(
    std::ostream& os,
    ipv6_address const& addr);

std::ostream&
operator<<(
    std::ostream& os,
    authority_view const& a);

std::ostream&
operator<<(
    std::ostream& os,
    decode_view const& s);

std::ostream&
operator<<(
    std::ostream& os,
    params_encoded_base const& qp);

std::ostream&
operator<<(
    std::ostream& os,
    params_base const& qp);

std::ostream&
operator<<(
    std::ostream& os,
    segments_encoded_base const& ps);

std::ostream&
operator<<(
    std::ostream& os,
    segments_base const& ps);

std::ostream&
operator<<(
    std::ostream& os,
    url_view_base const& u);