# $msg is the message to send, it is guaranteed < PIPE_BUF and ends in \r\n
        my $sigpipe = 0;
        local $SIG{PIPE} = sub {
            $sigpipe = 1;
        };
        my $sent = print $child_writer $msg;
        if (!$sent && ($!{EPIPE} || $sigpipe)) {
            warn "Write to child_writer failed with EPIPE - child died ($sigpipe)");
            # restarts child writer
        } else {
            warn "Write to child_writer failed - $!";
        }