X-Cache-Segment holds all cookies 

if 'segment_checksum' is not set X-Cache-Segment holds all cookies.
additional check needed
e.g.
```
sub normalize_customer_segment {
    unset req.http.X-Cache-Segment;
    if( req.http.Cookie ~ "segment_checksum" ) {
        set req.http.X-Cache-Segment = regsuball(req.http.Cookie, "^.*segment_checksum=([a-zA-Z0-9]+).*$", "\1");
        if (req.http.X-Cache-Segment) {
            set client.identity = client.identity + req.http.X-Cache-Segment; 
        }
    }
}
```