public static boolean reserved(Uuid uuid) {
        return uuid.getMostSignificantBits() == 0 &&
            uuid.getLeastSignificantBits() < 100;
    }
Check if a directory ID is part of the first 100 reserved IDs.

@param uuid the directory ID to check.
@return     true only if the directory ID is reserved.
server-common/src/main/java/org/apache/kafka/common/DirectoryId.java