How to use the minizlib.Gzip function in minizlib

const check = t => {
    const entries = fs.readdirSync(dir)
    t.equal(entries.length, 1)
    t.equal(entries[0], 'd')
    Object.keys(expect).forEach(f => {
      const file = dir + '/' + f
      t.equal(fs.readFileSync(file, 'utf8'), expect[f])
    })
    t.end()
  }

  const unpack = new Unpack({ cwd: dir, strip: 8 })
  const data = fs.readFileSync(tars + '/long-paths.tar')
  // while we're at it, why not use gzip too?
  const zip = new z.Gzip()
  zip.pipe(unpack)
  unpack.on('close', _ => check(t))
  zip.end(data)
})

if (body && !bodyIsStream && !bodyIsPromise && typeof body !== 'string' && !Buffer.isBuffer(body)) {
    headers['content-type'] = headers['content-type'] || 'application/json'
    body = JSON.stringify(body)
  } else if (body && !headers['content-type']) {
    headers['content-type'] = 'application/octet-stream'
  }

  if (opts.gzip) {
    headers['content-encoding'] = 'gzip'
    if (bodyIsStream) {
      const gz = new zlib.Gzip()
      body.on('error', /* istanbul ignore next: unlikely and hard to test */
        err => gz.emit('error', err))
      body = body.pipe(gz)
    } else if (!bodyIsPromise) {
      body = new zlib.Gzip().end(body).concat()
    }
  }

  if (opts.query) {
    const q = typeof opts.query === 'string'
      ? qs.parse(opts.query)
      : opts.query

    const parsed = new url.URL(uri)
    Object.keys(q).forEach(key => {
      if (q[key] !== undefined) {
        parsed.searchParams.set(key, q[key])
      }
    })
    uri = url.format(parsed)
  }

const bodyIsStream = Minipass.isStream(body)
  const bodyIsPromise = body &&
    typeof body === 'object' &&
    typeof body.then === 'function'

  if (body && !bodyIsStream && !bodyIsPromise && typeof body !== 'string' && !Buffer.isBuffer(body)) {
    headers['content-type'] = headers['content-type'] || 'application/json'
    body = JSON.stringify(body)
  } else if (body && !headers['content-type']) {
    headers['content-type'] = 'application/octet-stream'
  }

  if (opts.gzip) {
    headers['content-encoding'] = 'gzip'
    if (bodyIsStream) {
      const gz = new zlib.Gzip()
      body.on('error', /* istanbul ignore next: unlikely and hard to test */
        err => gz.emit('error', err))
      body = body.pipe(gz)
    } else if (!bodyIsPromise) {
      body = new zlib.Gzip().end(body).concat()
    }
  }

  if (opts.query) {
    const q = typeof opts.query === 'string'
      ? qs.parse(opts.query)
      : opts.query

    const parsed = new url.URL(uri)
    Object.keys(q).forEach(key => {
      if (q[key] !== undefined) {

this.preservePaths = !!opt.preservePaths
    this.strict = !!opt.strict
    this.noPax = !!opt.noPax
    this.prefix = (opt.prefix || '').replace(/(\\|\/)+$/, '')
    this.linkCache = opt.linkCache || new Map()
    this.statCache = opt.statCache || new Map()
    this.readdirCache = opt.readdirCache || new Map()
    this[WRITEENTRYCLASS] = WriteEntry
    if (typeof opt.onwarn === 'function')
      this.on('warn', opt.onwarn)

    this.zip = null
    if (opt.gzip) {
      if (typeof opt.gzip !== 'object')
        opt.gzip = {}
      this.zip = new zlib.Gzip(opt.gzip)
      this.zip.on('data', chunk => super.write(chunk))
      this.zip.on('end', _ => super.end())
      this.zip.on('drain', _ => this[ONDRAIN]())
      this.on('resume', _ => this.zip.resume())
    } else
      this.on('drain', this[ONDRAIN])

    this.portable = !!opt.portable
    this.noDirRecurse = !!opt.noDirRecurse
    this.follow = !!opt.follow
    this.noMtime = !!opt.noMtime
    this.mtime = opt.mtime || null

    this.filter = typeof opt.filter === 'function' ? opt.filter : _ => true

    this[QUEUE] = new Yallist

function fastPathGzip(bufferOrString, options) {
  return streamToBuffer(new Gzip(options), bufferOrString)
}

static gzip(bufferOrString, options) {
    options = utils.createOptions(options, DEFAULT_GZIP_CONFIG)

    if (useGzipFastPath) {
      try {
        return streamToBuffer(new minizlib.Gzip(options), bufferOrString)
      } catch (e) {
        useGzipFastPath = false
      }
    }
    return fallbackGzip(bufferOrString, options)
  }

this.linkCache = opt.linkCache || new Map()
    this.statCache = opt.statCache || new Map()
    this.readdirCache = opt.readdirCache || new Map()

    this[WRITEENTRYCLASS] = WriteEntry
    if (typeof opt.onwarn === 'function')
      this.on('warn', opt.onwarn)

    this.portable = !!opt.portable
    this.zip = null
    if (opt.gzip) {
      if (typeof opt.gzip !== 'object')
        opt.gzip = {}
      if (this.portable)
        opt.gzip.portable = true
      this.zip = new zlib.Gzip(opt.gzip)
      this.zip.on('data', chunk => super.write(chunk))
      this.zip.on('end', _ => super.end())
      this.zip.on('drain', _ => this[ONDRAIN]())
      this.on('resume', _ => this.zip.resume())
    } else
      this.on('drain', this[ONDRAIN])

    this.noDirRecurse = !!opt.noDirRecurse
    this.follow = !!opt.follow
    this.noMtime = !!opt.noMtime
    this.mtime = opt.mtime || null

    this.filter = typeof opt.filter === 'function' ? opt.filter : _ => true

    this[QUEUE] = new Yallist
    this[JOBS] = 0