public static function start(ExporterInterface $reporter, array $options = [])
    {
        $sampler = array_key_exists('sampler', $options)
            ? $options['sampler']
            : new AlwaysSampleSampler();
        unset($options['sampler']);

        $propagator = array_key_exists('propagator', $options)
            ? $options['propagator']
            : new HttpHeaderPropagator();
        unset($options['propagator']);

        return self::$instance = new RequestHandler($reporter, $sampler, $propagator, $options);
    }