code: public RemoteIterator<LocatedFileStatus> listFiles(Path f, boolean recursive) throws FileNotFoundException, IOException {
      try (Closeable context = new TimerContextWithLog(this.listFilesTimer.time(), "listFiles", f, recursive)) {
        return super.listFiles(f, recursive);
      }
    }
docs: Add timer metrics to {@link FileSystem#listFiles(Path, boolean)}