*       type.
 * </dl>
 *
 * <h2>Ranges</h2>
 *
 * <ul>
 *   <li>{@link Range}
 *   <li>{@link RangeMap}
 *   <li>{@link RangeSet}
 *   <li>{@link DiscreteDomain}
 *   <li>{@link ContiguousSet}
 * </ul>
 *
 * <h2>Classes of static utility methods</h2>
 *
 * <ul>
 *   <li>{@link Collections2}
 *   <li>{@link Comparators}
 *   <li>{@link Iterables}

 *       type.
 * </dl>
 *
 * <h2>Ranges</h2>
 *
 * <ul>
 *   <li>{@link Range}
 *   <li>{@link RangeMap}
 *   <li>{@link RangeSet}
 *   <li>{@link DiscreteDomain}
 *   <li>{@link ContiguousSet}
 * </ul>
 *
 * <h2>Classes of static utility methods</h2>
 *
 * <ul>
 *   <li>{@link Collections2}
 *   <li>{@link Comparators}
 *   <li>{@link Iterables}

 *
 * <p>The DataIndexHelper supports:</p>
 * <ul>
 *   <li>Concurrent crawling of multiple data configurations</li>
 *   <li>Thread pool management for crawler execution</li>
 *   <li>Session-based crawling with cleanup operations</li>
 *   <li>Old document deletion after successful crawling</li>
 *   <li>Crawling execution monitoring and timing</li>
 * </ul>
 */
public class DataIndexHelper {

 *
 * <p>Cache statistics are incremented according to the following rules:
 *
 * <ul>
 *   <li>When a cache lookup encounters an existing cache entry {@code hitCount} is incremented.
 *   <li>When a cache lookup first encounters a missing cache entry, a new entry is loaded.
 *       <ul>
 *         <li>After successfully loading an entry {@code missCount} and {@code loadSuccessCount}

 * It implements the Closeable interface to ensure that resources are properly released.
 *
 * <p>This class supports two types of content caching:
 * <ul>
 *   <li>In-memory caching using a byte array</li>
 *   <li>File-based caching using a File object</li>
 * </ul>
 *
 * <p>When an instance of ContentCache is created with a byte array, the content is cached in memory.

 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.

 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.

 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.

 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.

 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.