protected function addTraceSpan($unsetParentId = true)
    {
        $span = new Span(
            TracerInfo::getTraceSpanId(),
            $this->name,
            new AnnotationBlock(
                $this->endpoint,
                $this->startTimestamp,
                zipkin_timestamp(),
                AnnotationBlock::SERVER
            )
        );
        if ($unsetParentId) {
            $span->unsetParentId();
        }
        $this->addSpan($span);
    }