How to handle bounce email with postfix and php?

问题

Using Postfix and PHP i would like to handle bounce email.

I first build a postfix server like this :

https://www.digitalocean.com/community/tutorials/how-to-set-up-a-postfix-e-mail-server-with-dovecot

then master.cf configuration from

https://thecodingmachine.io/triggering-a-php-script-when-your-postfix-server-receives-a-mail

I'm able to send all outgoing email content to my php script, but how can i only send bounce email to this script ?

Mail sender:

$headers[] = 'MIME-Version: 1.0';
$headers[] = 'Content-type: text/html; charset=iso-8859-1';
$headers[] = 'Reply-To: bounce@example.com';
$headers[] = 'Return-Path: bounce@example.com';
$headers[] = 'From: Example <postmaster@example.com>'


mail('Example <example@example.com>', "subject", "msg", implode("\r\n", $headers), "-f bounce@example.com");

master.cf pickup send all outgoing email to example.php. I tried to use bounce instead of pickup but without success.

pickup    fifo  n       -       -       60      1       pickup
       -o content_filter=myhook:dummy

myhook unix - n n - - pipe
  flags=F user=www-data argv=/var/www/example.php ${sender} ${size} ${recipient}

What i am doing wrong ?

Thanks