Open WebUI Tracking per user cost.

I’ve set up Open WebUI with LiteLLM. I have many users, and I need to track usage and costs on a per-user basis (tokens and estimated spend per user). However, I can’t figure out how to correctly pass user identity from Open WebUI to LiteLLM and how to configure LiteLLM so that it reports usage/costs per individual user. Any help would be appreciated.