First, set up an ngrok tunnel. Download ngrok if you don't already have it: brew install ngrok/ngrok/ngrok
Start a TCP tunnel like ngrok tcp 1025. 1025 is the local port that will receive traffic for the mini-pov.
Go into Starwood's admin console. Navigate to Apps > Google Workspace > Settings for Gmail > Hosts and edit the test pipe route. Ensure this route's Single host value matches that of the ngrok tunnel you just started.
Open a new terminal window and navigate to the root of this repo. Do go run main.go to start the server. Now outbound emails will be routed to this server on their way to the destination.