Tolerance\Tracer\SpanStack\SpanStack::push PHP Method

    public function push(Span $span);

 /**
  * @param GetResponseEvent $event
  */
 public function onKernelRequest(GetResponseEvent $event)
 {
     if (!$event->isMasterRequest()) {
         return;
     }
     $span = $this->httpFoundationSpanFactory->fromIncomingRequest($event->getRequest());
     $this->stack->push($span);
     $this->tracer->trace([$span]);
 }