public boolean isEqual() {
            return isEqual;
        }
Check whether this FileSegment is expired, and set expire status.
The last FileSegment cannot be marked expired.

@param checkTimestamp check timestamp.
@param maxValidTimeMs the max expire interval in milliseconds.
@return -1 means already expired, 0 means the last FileSegment, 1 means expired.
inlong-tubemq/tubemq-server/src/main/java/org/apache/inlong/tubemq/server/broker/msgstore/disk/FileSegment.java