text: 'use strict';
  
  const fs = require('fs');
  const fileName = './sync.txt';
  
  console.time("time"); // 計測開始
  for (let count = 0; count < 256; count++) {
    fs.appendFileSync(fileName, `${count}:\t`, 'utf8', ()=> {});
    fs.appendFileSync(fileName, 'あ', 'utf8', ()=> {});
    fs.appendFileSync(fileName, 'い', 'utf8', ()=> {});
    fs.appendFileSync(fileName, 'う', 'utf8', ()=> {});
    fs.appendFileSync(fileName, 'え', 'utf8', ()=> {});
    fs.appendFileSync(fileName, 'お', 'utf8', ()=> {});
    fs.appendFileSync(fileName, '\n', 'utf8', ()=> {});
    console.timeLog("time"); // 必要に応じて
  }
  console.timeEnd("time"); // 計測終了