@Override
    public long getRecordTime(long reqOffset) throws IOException {
        ByteBuffer readUnit = ByteBuffer.allocate(DataStoreUtils.STORE_INDEX_HEAD_LEN);
        int size = 0;
        while (readUnit.hasRemaining()) {
            final int l = this.channel.read(readUnit, reqOffset - start + size);
            if (l < 0) {
                break;
            }
            size += l;
        }
        readUnit.flip();
        return readUnit.getLong(DataStoreUtils.INDEX_POS_TIME_RECV);
    }
read index record's append time.
@param reqOffset request offset.
@return message append time.
inlong-tubemq/tubemq-server/src/main/java/org/apache/inlong/tubemq/server/broker/msgstore/disk/FileSegment.java