Request body: limited chunk extensions and trailer headers. Previously, arbitrary amounts of chunk extensions and trailer headers were accepted and skipped. Despite being under limit_conn / limit_req limits (if configured), this can be a DoS vector, so it is now limited by the client_max_body_size limit. Reported by Bartek Nowotarski.

--- a/src/http/ngx_http.h
+++ b/src/http/ngx_http.h
@@ -65,6 +65,7 @@ struct ngx_http_chunked_s {
     ngx_uint_t           state;
     off_t                size;
     off_t                length;
+    off_t                skipped;
 };