不支持http header透传？

[isyntop]

/**
 * 注入
 * @param SpanContext $spanContext
 * @param string $format
 * @param $carrier
 */
public function inject(SpanContext $spanContext, $format, &$carrier){
    if($format == Formats\TEXT_MAP){
        $this->propagator->inject($spanContext, $format, $carrier);
    }else{
        throw new \Exception("not support format $format");
    }
}


/**
 * 提取
 * @param string $format
 * @param $carrier
 */
public function extract($format, $carrier){
    if($format == Formats\TEXT_MAP){
        return $this->propagator->extract($format, $carrier);
    }else{
        throw new \Exception("not support format $format");
    }
}

const HTTP_HEADERS = 'http_headers'; 不支持http header透传？

[jukylin]

期待你提个pr