@InterfaceAudience.Private
  protected void init(final byte[] encodedRegionName, final TableName tablename, long logSeqNum,
    final long now, List<UUID> clusterIds, long nonceGroup, long nonce,
    MultiVersionConcurrencyControl mvcc, NavigableMap<byte[], Integer> replicationScope,
    Map<String, byte[]> extendedAttributes) {
    this.sequenceId = logSeqNum;
    this.writeTime = now;
    this.clusterIds = clusterIds;
    this.encodedRegionName = encodedRegionName;
    this.tablename = tablename;
    this.nonceGroup = nonceGroup;
    this.nonce = nonce;
    this.mvcc = mvcc;
    if (logSeqNum != NO_SEQUENCE_ID) {
      setSequenceId(logSeqNum);
    }
    this.replicationScope = replicationScope;
    this.extendedAttributes = extendedAttributes;
  }
Create the log key for writing to somewhere. We maintain the tablename mainly for debugging
purposes. A regionName is always a sub-table object.
@param encodedRegionName Encoded name of the region as returned by
                         <code>HRegionInfo#getEncodedNameAsBytes()</code>.
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/WALKeyImpl.java