Method JsonValue

tests/Timeline.cpp:195–200

	std::string Json() const override { return JsonValue().toStyledString(); }
	Json::Value JsonValue() const override {
		Json::Value root = ReaderBase::JsonValue();
		root["type"] = "TimelineConstantAudioReader";
		root["path"] = "";
		return root;
	}
	void SetJson(const std::string value) override { (void) value; }
	void SetJsonValue(const Json::Value root) override { ReaderBase::SetJsonValue(root); }
};