if (my $s1 = $self->{-wq_s1}) { # run in worker
my $fds = [ map { fileno($_) } @$ios ];
my $n = $send_cmd->($s1, $fds, freeze([$sub, @args]), MSG_EOR);
if (my $s1 = $self->{-wq_s1}) { # run in worker
my $fds = [ map { fileno($_) } @$ios ];
my $n = $send_cmd->($s1, $fds, freeze([$sub, @args]), MSG_EOR);