From fc1dfa1ceb8897bcaa5231b560b9319591d4ab0a Mon Sep 17 00:00:00 2001
From: Alex Bramley <a.bramley@gmail.com>
Date: Fri, 16 Feb 2018 21:04:56 +0000
Subject: [PATCH] Add net.Dialer DualStack config option.

---
 client/connection.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/client/connection.go b/client/connection.go
index f84621a..12d0e59 100644
--- a/client/connection.go
+++ b/client/connection.go
@@ -82,6 +82,11 @@ type Config struct {
 	// Local address to bind to when connecting to the server.
 	LocalAddr string
 
+	// To attempt RFC6555 parallel IPv4 and IPv6 connections if both
+	// address families are returned for a hostname, set this to true.
+	// Passed through to https://golang.org/pkg/net/#Dialer
+	DualStack bool
+
 	// Replaceable function to customise the 433 handler's new nick.
 	// By default an underscore "_" is appended to the current nick.
 	NewNick func(string) string
@@ -160,6 +165,7 @@ func Client(cfg *Config) *Conn {
 
 	dialer := new(net.Dialer)
 	dialer.Timeout = cfg.Timeout
+	dialer.DualStack = cfg.DualStack
 	if cfg.LocalAddr != "" {
 		if !hasPort(cfg.LocalAddr) {
 			cfg.LocalAddr += ":0"