nginx rate limiting with X-Forwarded-For header

I'm looking into rate-limiting using nginx's HttpLimitReqModule. However, requests are all coming from the same IP (a loadbalancer), with the real IP address in the headers. Is there a way to have nginx rate-limit based on the ip in the X-Forwarded-For header instead of the ip of the source?

[inoueyuworks]

Rate Limiting において、"If you use realip module, $binary_remote_addr variable gets set correctly. "