@InterfaceAudience.Private
  protected void setSequenceId(long sequenceId) {
    this.sequenceId = sequenceId;
  }
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