/**
     * Constructs a new {@code CrawlerSystemException} with the specified detail message and cause.
     *
     * @param message the detail message (which is saved for later retrieval by the {@link #getMessage()} method).
     * @param cause the cause (which is saved for later retrieval by the {@link #getCause()} method).
     *              (A {@code null} value is permitted, and indicates that the cause is nonexistent or unknown.)
     */