default void postAppend(final long entryLen, final long elapsedTimeMillis, final WALKey logKey,
    final WALEdit logEdit) throws IOException {
  }
For notification post append to the writer. Used by metrics system at least. TODO: Combine this
with above.
@param entryLen          approx length of cells in this append.
@param elapsedTimeMillis elapsed time in milliseconds.
@param logKey            A WAL key
@param logEdit           A WAL edit containing list of cells.
@throws IOException if any network or I/O error occurred
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/WALActionsListener.java