@Override
  public void postAppend(final long size, final long time, final WALKey logkey,
    final WALEdit logEdit) throws IOException {
    TableName tableName = logkey.getTableName();
    source.incrementAppendCount(tableName);
    source.incrementAppendTime(time);
    source.incrementAppendSize(tableName, size);
    source.incrementWrittenBytes(size);

    if (time > 1000) {
      source.incrementSlowAppendCount();
      LOG.warn(String.format("%s took %d ms appending an edit to wal; len~=%s",
        Thread.currentThread().getName(), time, Strings.humanReadableInt(size)));
    }
  }
Class used to push numbers about the WAL into the metrics subsystem. This will take a single
function call and turn it into multiple manipulations of the hadoop metrics system.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/MetricsWAL.java