$ua->proxy('http','http://myuser:mypass@10.0.4.77');
$ua->proxy(http =>'http://myuser:mypass@10.0.4.77');
$ua->proxy('http','http://10.0.4.77');
$ua->proxy('http','http://10.0.4.77:80');
$ua->proxy('http','http://myuser:mypass@10.0.4.77:80');