code: async function compareStream (filename, expectedContents) {
    try {
      const actualStream = fs.createReadStream(filename)
      const result = await streamCompare(expectedContents, actualStream, {
        abortOnError: true,
        compare: (a, b) => {
          return Buffer.compare(a.data, b.data) !== 0
        }
      })
      return result
    } catch (err) {
      return handleError(err)
    }
  }
docs: Compares a readable stream with a file contents. Returns true, if they differ or the file does not exist.
  @param {string} filename the file name
  @param {Stream} expectedContents the file contents
  @returns {Promise<boolean>|boolean}
  @private