Function extract_request_forwarded_for 

pub fn extract_request_forwarded_for<B>(
    request: &Request<B>,
) -> Result<Option<Vec<IpAddr>>, Error>

Extract the untrusted Forwarded for= IP chain from a complete request.

This reads request.headers() and delegates to extract_header_forwarded_for, preserving its missing and strict error behavior. It does not establish trust in the returned assertions.