@Override
  public void append(EntryBuffers.RegionEntryBuffer buffer) throws IOException {
    List<WAL.Entry> entries = buffer.entryBuffer;
    if (entries.isEmpty()) {
      LOG.warn("got an empty buffer, skipping");
      return;
    }
    RecoveredEditsWriter writer = getRecoveredEditsWriter(buffer.tableName,
      buffer.encodedRegionName, entries.get(0).getKey().getSequenceId());
    if (writer != null) {
      writer.writeRegionEntries(entries);
    }
  }
Class that manages the output streams from the log splitting process. Every region only has one
recovered edits file PER split WAL (if we split multiple WALs during a log-splitting session, on
open, a Region may have multiple recovered.edits files to replay -- one per split WAL).
@see BoundedRecoveredEditsOutputSink which is like this class but imposes upper bound on the
     number of writers active at one time (makes for better throughput).
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/RecoveredEditsOutputSink.java