Allow defining which context data to be added to timeline entries

src/DebugbarSubscriber.php

@@ -105,6 +105,16 @@ public function onError(ErrorEvent $event)
         }
     }
 
+    /**
+     * Set the keys to be used when adding context to a time-line entry.
+     *
+     * @param array $contextKeys
+     */
+    public function setContextKeys(array $contextKeys)
+    {
+        $this->context = $contextKeys;
+    }
+
     /**
      * Start a measurement for a request.
      *