Variable $bytes_sent.

It replicates variable $bytes_sent as previously available in log module
only.

Patch by Benjamin Grössing (with minor changes).

src/http/ngx_http_variables.c

diff --git a/src/http/ngx_http_variables.c b/src/http/ngx_http_variables.c
index f34a6d9..e513279 100644
--- a/src/http/ngx_http_variables.c
+++ b/src/http/ngx_http_variables.c
@@ -69,6 +69,8 @@
     ngx_http_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_http_variable_remote_user(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
+static ngx_int_t ngx_http_variable_bytes_sent(ngx_http_request_t *r,
+    ngx_http_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_http_variable_body_bytes_sent(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_http_variable_request_completion(ngx_http_request_t *r,
@@ -212,6 +214,9 @@
 
     { ngx_string("remote_user"), NULL, ngx_http_variable_remote_user, 0, 0, 0 },
 
+    { ngx_string("bytes_sent"), NULL, ngx_http_variable_bytes_sent,
+      0, 0, 0 },
+
     { ngx_string("body_bytes_sent"), NULL, ngx_http_variable_body_bytes_sent,
       0, 0, 0 },
 
@@ -1434,6 +1439,27 @@
 
 
 static ngx_int_t
+ngx_http_variable_bytes_sent(ngx_http_request_t *r,
+    ngx_http_variable_value_t *v, uintptr_t data)
+{
+    u_char  *p;
+
+    p = ngx_pnalloc(r->pool, NGX_OFF_T_LEN);
+    if (p == NULL) {
+        return NGX_ERROR;
+    }
+
+    v->len = ngx_sprintf(p, "%O", r->connection->sent) - p;
+    v->valid = 1;
+    v->no_cacheable = 0;
+    v->not_found = 0;
+    v->data = p;
+
+    return NGX_OK;
+}
+
+
+static ngx_int_t
 ngx_http_variable_body_bytes_sent(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data)
 {