newrelic_is_sampled

newrelic_is_sampled()

function make_http_request($url) {
    $metadata = newrelic_get_trace_metadata();
    $sampled = newrelic_is_sampled();

    $ch = curl_init($url);

    curl_setopt($ch, CURLOPT_HTTPHEADER, array(
        'X-B3-TraceId: ' . $metadata['trace_id'],
        'X-B3-SpanId: ' . substr(uniqid() . uniqid(), 0, 16),
        'X-B3-ParentSpanId: ' . $metadata['span_id'],
        'X-B3-Sampled: ' . $sampled));

    return curl_exec($ch);
}

$status = make_http_request("zipkin-consumer.example");