How can I serve unbuffered CGI content from Apache 2?

Randal Schwartz's article Watching long processes through CGI explains a different (and IMHO, better) way of watching a long running process.

Flushing STDOUT can help. For example, the following Perl program should work as intended:

#!/usr/bin/perl

use strict;
use warnings;

local $| = 1;

print "Content-type: text/plain\n\n";

for ( my $i = 1 ; $i <= 10 ; $i++ ) {
    print "$i\n";
    sleep(1);
}

print "Done.";