code: func (p *PerHost) Dial(network, addr string) (c net.Conn, err error) {
  	host, _, err := net.SplitHostPort(addr)
  	if err != nil {
  		return nil, err
  	}
  
  	return p.dialerForRequest(host).Dial(network, addr)
  }
docs: // Dial connects to the address addr on the given network through either
  // defaultDialer or bypass.