@Override
  public boolean close() {
    if (bufferedWriter != null) {
      try {
        bufferedWriter.close();
      } catch (Exception e) {
        e.printStackTrace();
      }
    }
    bufferedWriter = null;
    logFileName = null;
    logFile = null;
    return true;
  }
Called after a log file is newly created.
<p>
You can do some initialization work to the new file, such as calling {@link #appendLog(String)}
to add a file header.
<p>
Called in worker thread.

@param file the newly created log file
xlog/src/main/java/com/elvishew/xlog/printer/file/writer/SimpleWriter.java