my $cmd = [qw(curl --tcp-nodelay --no-buffer -T- -HExpect: -sS), $url];
open my $cout, '+>', undef or die;
open my $cerr, '>', undef or die;
- my $rdr = { 0 => fileno($r), 1 => fileno($cout), 2 => fileno($cerr) };
+ my $rdr = { 0 => $r, 1 => $cout, 2 => $cerr };
my $pid = spawn($cmd, undef, $rdr);
close $r or die "close read pipe: $!";
foreach my $c ('a'..'z') {