How to Enable Immediate CGI Line Outputs With Nginx, Without Waiting for a CGI Script to Finish?

I have a perl and shell script that process a bunch of data and output results as they happen, like:

5 processed in 0.58 seconds.
10 processed in 0.79 seconds.
...
150 processed in 0.65 seconds. DONE!

etc.

However, when I visit the URL with Chrome, it shows nothing, waits until the script finishes, then shows the entire output at once. Is there a way to configure nginx to show each line output as it happens? I used to be able to do this with Apache.

I put gzip off in the nginx config, thinking this could nginx waiting to compress the text before sending it to the client, but that did not help.

I also tried buffer-flushing techniques in the scripts themselves, like these lines at the top of my Perl scripts:

use IO::Handle;
$| ++;
STDERR->autoflush(1);
STDOUT->autoflush(1);
print "Content-type: text/plainnn";

Relevant parts of the nginx config look like this

  ssl on;
  root /my/path/cgi ;
  proxy_read_timeout 900s ;
  fastcgi_read_timeout 900s ;
  fastcgi_request_buffering off ;
  gzip off ;
  location ~ .pl|cgi$ {
    try_files $uri =404;
    gzip off;
    fastcgi_pass  unix:/var/run/fcgiwrap.socket;
    include /etc/nginx/fastcgi_params;
    fastcgi_param SCRIPT_FILENAME  $document_root$fastcgi_script_name;
  }

Any ideas?