use strict;
use vars qw($header_printed);
$header_printed = 0;

print_header("text/plain");
print "It worked!\n";
print_header("text/plain");

sub print_header {
    return if $header_printed;
    
    my $type = shift || "text/html";
    $header_printed = 1;
    my $r = Apache->request;
    $r->content_type($type);
    $r->send_http_header;
}
1;