Forum: NGINX log module

hello:
   when i using the log module to write the acess_log.there are three 
set-cookie  line in  reponse hearders, But the log module only writes 
the first set-cookie of response headers into log.
  here is my log_format:
      log_format  main  '$remote_addr - $remote_user [$time_local] 
"$request" '
          '$status $body_bytes_sent "$http_referer" '
          '"$http_user_agent" "$http_x_forwarded_for" $upstream_addr '
          '$http_cookie $request_time set_cookie=$sent_http_set_cookie';