public function linkAdded(Span $span, Link $link)
    {
        // If the span is already attached (managed by the extension), then
        // tell the extension to add the link.
        if ($span->attached()) {
            $this->addLink($link->traceId(), $link->spanId(), [
                'type' => $link->type(),
                'attributes' => $link->attributes(),
                'span' => $span
            ]);
        }
    }