Why does `sampler` not support `PercentageSampler`

[summerKK]

Can we consider making a configuration option to support PercentageSampler?
Sampling may be employed to reduce the data collected and reported out of process.
https://github.com/openzipkin/zipkin-php#sampling

    public function createZipkinDriver()
    {
        $tracer = new ZipkinTracer(
            $this->config->get('tracing.service_name'),
            $this->config->get('tracing.zipkin.host'),
            $this->config->get('tracing.zipkin.port'),
            $this->config->get('tracing.zipkin.options.128bit'),
            $this->config->get('tracing.zipkin.options.request_timeout', 5)
        );

        ZipkinTracer::setMaxTagLen(
            $this->config->get('tracing.zipkin.options.max_tag_len', ZipkinTracer::getMaxTagLen())
        );

        return $tracer->init();
    }

    public function init(): Tracer
    {
        $this->tracing = TracingBuilder::create()
            ->havingLocalEndpoint($this->createEndpoint())
            ->havingTraceId128bits($this->usesTraceId128bits)
            ->havingSampler($this->createSampler())
            ->havingReporter($this->createReporter())
            ->build();

        $this->registerDefaultExtractionFormats();
        $this->registerDefaultInjectionFormats();

        return $this;
    }

    protected function createSampler(): Sampler
    {
        return BinarySampler::createAsAlwaysSample();
    }