Tinyproxy version

tinyproxy version 1.10.0 running on an OpenWRT (x64) system

Issue

I have a Wireguard tunnel set up, with a unique IP address that I bind tinyproxy to. I want all proxied traffic to go via this tunnel. I don't have (or need) any upstream proxies. Currently, whatever I do, the proxied traffic goes out directly. On https://tinyproxy.github.io/ it says:

Bind
This allows you to specify which address Tinyproxy will bind to for
outgoing connections to web servers or upstream proxies.

(emphasis mine)

But I can't figure out if this is even possible without an upstream proxy.