code: function makeTempFile() {
      const n = Math.floor(Math.random() * 100000)
      const tempFile = path.join(os.tmpdir(), `node-exiftool_test_${n}.jpg`)
      return new Promise((resolve, reject) => {
          const rs = fs.createReadStream(jpegFile)
          const ws = fs.createWriteStream(tempFile)
          rs.on('error', reject)
          ws.on('error', reject)
          ws.on('close', () => {
              resolve(tempFile)
          })
          rs.pipe(ws)
      })
  }
docs: create temp file for writing metadata