I was surprised by your use of sleep in a controller.  I'd been under the impression that using sleep would put the entire web server to sleep and slow down connections for other users.  After some research it seems this is only true for single threaded servers like WEBrick.  But then I looked up the default server for Heroku, and it's WEBrick.   Do I have my facts right?   Am I correct in assuming that calling sleep in a controller and then using the default Heroku server will slow requests for all users?

Is this still good practice in a rails 5.2 project?  Or are there better ways to handle this now?