void internTableName(TableName tablename) {
    // We should not use this as a setter - only to swap
    // in a new reference to the same table name.
    assert tablename.equals(this.tablename);
    this.tablename = tablename;
  }
Drop this instance's tablename byte array and instead hold a reference to the provided
tablename. This is not meant to be a general purpose setter - it's only used to collapse
references to conserve memory.
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/WALKeyImpl.java