I need to do some additional processing after a Drupal page has been sent.

I know I could fire a background shell command, but I need the current Drupal execution context to be maintained.

I've spent a lot of time looking, but I can't find any documentation in this regard. This is surprising because it must surely be a common requirement.

The only real idea I have is to fire up Drupal (again) via a shell command (exec, etc) and supply it with a pseudo path which would invoke the continued processing. But this seems unnecessarily complex/wasteful.

Any pointers greatly appreciated, tks.