Create an address from an IP address string in dotted decimal form.

static address_v4 from_string(
    const char * str);

static address_v4 from_string(
    const char * str,
    asio::error_code & ec);

static address_v4 from_string(
    const std::string & str);

static address_v4 from_string(
    const std::string & str,
    asio::error_code & ec);