code: func (d *TCPDialer) Dial(addr string) (net.Conn, error) {
  	return d.dial(addr, false, DefaultDialTimeout)
  }
docs: // Dial dials the given TCP addr using tcp4.
  //
  // This function has the following additional features comparing to net.Dial:
  //
  //   * It reduces load on DNS resolver by caching resolved TCP addressed
  //     for DefaultDNSCacheDuration.
  //   * It dials all the resolved TCP addresses in round-robin manner until
  //     connection is established. This may be useful if certain addresses
  //     are temporarily unreachable.
  //   * It returns ErrDialTimeout if connection cannot be established during
  //     DefaultDialTimeout seconds. Use DialTimeout for customizing dial timeout.
  //
  // This dialer is intended for custom code wrapping before passing
  // to Client.Dial or HostClient.Dial.
  //
  // For instance, per-host counters and/or limits may be implemented
  // by such wrappers.
  //
  // The addr passed to the function must contain port. Example addr values:
  //
  //     * foobar.baz:443
  //     * foo.bar:80
  //     * aaa.com:8080