/** Constant for Kryo serializer type. */
    protected static final String KRYO = "kryo";

    /** ThreadLocal container for Kryo instances to ensure thread safety. */
    protected final ThreadLocal<Kryo> kryoThreadLocal;

    /**
     * Constructs a new DataSerializer.
     * <p>
     * Initializes the ThreadLocal Kryo instances with appropriate configuration.
     * The Kryo instances are configured to not require class registration for

			<artifactId>bcprov-jdk18on</artifactId>
			<version>${bouncycastle.version}</version>
		</dependency>
		<dependency>
			<groupId>com.esotericsoftware</groupId>
			<artifactId>kryo</artifactId>
			<version>${kryo.version}</version>
		</dependency>

		<!-- suggest library -->
		<dependency>
			<groupId>org.codelibs.fess</groupId>
			<artifactId>fess-suggest</artifactId>

# Default script for the crawler (e.g., groovy).
crawler.default.script=groovy
# Number of threads for HTTP crawling.
crawler.http.thread_pool.size=0
# Serializer type for crawler data (e.g., kryo).
crawler.data.serializer=kryo
# Maximum length of site name in documents.
crawler.document.max.site.length=100
# Encoding for site names in documents.
crawler.document.site.encoding=UTF-8
# Hostname to use when unknown in documents.

     */
    Integer getCrawlerHttpThreadPoolSizeAsInteger();

    /**
     * Get the value for the key 'crawler.data.serializer'. <br>
     * The value is, e.g. kryo <br>
     * comment: Serializer type for crawler data (e.g., kryo).
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getCrawlerDataSerializer();

    /**