public function __construct(CallEventFactory $callEventFactory, FeatureDetector $featureDetector)
{
$this->callEventFactory = $callEventFactory;
$this->isGeneratorImplicitNextSupported = $featureDetector->isSupported('generator.implicit-next');
$this->isGeneratorReturnSupported = $featureDetector->isSupported('generator.return');
$this->isHhvm = $featureDetector->isSupported('runtime.hhvm');
}