That thread doesn't really cover the same topic; close but not really. I'm looking to unbuffer output by avoiding Apache's CGI handler, that was more about preventing the user/browser from timing out when waiting on ANY data to appear.
As was said in the other thread by Merlyn:
This works under modern Apache, but under older Apache versions, the script
also had to be named nph-something to turn off the buffering. Consider the name
as a signal that Apache should do its own $| = 1 equivalent.
I don't know why it doesnt work under 2.0 apache, but try renaming the script "nph-..." and looking into the docs on CGI.pm.
That is how you get around apache's buffering.