private void tellListenersAboutPreLogRoll(final Path oldPath, final Path newPath)
    throws IOException {
    coprocessorHost.preWALRoll(oldPath, newPath);

    if (!this.listeners.isEmpty()) {
      for (WALActionsListener i : this.listeners) {
        i.preLogRoll(oldPath, newPath);
      }
    }
  }
Tell listeners about pre log roll.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/AbstractFSWAL.java