update c->sent in ngx_unix_send()
diff --git a/src/os/unix/ngx_send.c b/src/os/unix/ngx_send.c
index 5cbb128..e0d6900 100644
--- a/src/os/unix/ngx_send.c
+++ b/src/os/unix/ngx_send.c
@@ -40,6 +40,8 @@
                 wev->ready = 0;
             }
 
+            c->sent += n;
+
             return n;
         }