Is there a way to statically configure my port?

I am testing a chat with rendezvous using go-libp2p in Heroku. It is failing in Heroku because it’s using a dynamic port of its own instead of Heroku’s port. I would like to be able to hard code the port with the Heroku PORT environment variable. Is that possible?

You can specify a set of listen addresses with libp2p · github.com/libp2p/go-libp2p · pkg.go.dev. You’ll want to listen on /ip4/0.0.0.0/tcp/PORT, /ip4/0.0.0.0/udp/PORT/quic, /ip6/::/tcp/PORT, and /ip6/::/udp/PORT/quic.