code: private void logProgress(String fileOffset, boolean prefixNewLine)
            throws IOException {
      long now = System.currentTimeMillis();
      LogEntry entry = new LogEntry(now, componentID, fileOffset);
      String line = entry.toString();
      if(prefixNewLine) {
        lockFileStream.writeBytes(System.lineSeparator() + line);
      }
      else {
        lockFileStream.writeBytes(line);
      }
      lockFileStream.hflush();
  
      lastEntry = entry; // update this only after writing to hdfs
    }
docs: partial writes of prior lines