Request body: unbuffered reading. The r->request_body_no_buffering flag was introduced. It instructs client request body reading code to avoid reading the whole body, and to call post_handler early instead. The caller should use the ngx_http_read_unbuffered_request_body() function to read remaining parts of the body. Upstream module is now able to use this mode, if configured with the proxy_request_buffering directive.

--- a/src/http/ngx_http_variables.c
+++ b/src/http/ngx_http_variables.c
@@ -1081,6 +1081,10 @@ ngx_http_variable_content_length(ngx_htt
         v->no_cacheable = 0;
         v->not_found = 0;
 
+    } else if (r->reading_body) {
+        v->not_found = 1;
+        v->no_cacheable = 1;
+
     } else if (r->headers_in.content_length_n >= 0) {
         p = ngx_pnalloc(r->pool, NGX_OFF_T_LEN);
         if (p == NULL) {