Merge branch '2.0.x' into 1.0.x

Author: allflame

src/Bridge/RequestSpanListener.php

@@ -55,6 +55,11 @@ public function getOperationName(Request $request)
 
     public function onResponse(FilterResponseEvent $event)
     {
+        if ($this->spans->isEmpty()) {
+
+            return $this;
+        }
+
         $this->tracer->finish(
             $this->spans->pop()->addTag(new HttpCodeTag($event->getResponse()->getStatusCode()))
         );