protected long syncSlots(final FSDataOutputStream stream, final ByteSlot[] slots,
    final int offset, final int count) throws IOException {
    long totalSynced = 0;
    for (int i = 0; i < count; ++i) {
      final ByteSlot data = slots[offset + i];
      data.writeTo(stream);
      totalSynced += data.size();
    }

    syncStream(stream);
    sendPostSyncSignal();

    if (LOG.isTraceEnabled()) {
      LOG.trace("Sync slots=" + count + '/' + syncMaxSlot + ", flushed="
        + StringUtils.humanSize(totalSynced));
    }
    return totalSynced;
  }
Used to construct the name of the log directory for master procedures
hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/store/wal/WALProcedureStore.java